Interesting map, but I'm afraid a lot of people will find things to gripe about it, because history is seldom so clear cut and there is a lot of bad blood going 'round.
As such, I will restrict my comments to my own country.
As a Romanian, I enjoy the thought of Greater Romania back on the map, but if we're talking about the current ethnic distribution, then we run into problems and there are a few alterations that should be made - first off, Transdniestria was never a Romanian land. We got it as "war booty" during WW2 and, after Stalin annexed Bessarabia into the Soviet Union, he tacked it on the new Moldavian SSR as a way to add more Russian speakers into the mix to balance the overwhelmingly Romanian population in the rest of the territory (that, and the fact a lot of Romanians were deported to Siberia, including some of my relatives, and replaced with Russians). Thus, from our perspective, that bit of land is not ours, never was and they can keep it.
For the Budjak, the situation is a bit more tricky. It was part of the historical Bessarabia and during the middle ages it had a largely Romanian population, but since it was part of the Russian Empire during the 19th Century and then part of the Soviet union, the balance has slowly shifted towards other ethnicities, to the point where today, only 13% of the population are Romanian and spread thinly across the territory. As such, maybe we should just give it up as lost, mourn it's passing and move on, because I really don't like people who cling to each and every square centimetre of land they held at one point in history as "rightfully theirs" regardless of who lives there now, because they are the ones that bring about world wars. (for an illustrative example, please see the very active Hungarian right-wing nationalists, not that ours are any better XD)
Finally, Southern Dobruja. Like Transdniestria, we got that bit following a war, in this case the Second Balkan War of 1913, when the Romanian Army marched unopposed all the way to the Bulgarian Capital of Sofia and then promptly lost 6,000 men to cholera. Historically, it has only been under Romanian rule for 32 years (1388-1420) and was populated with all manner of ethnicities and a feeble Romanian minority. When, in 1878, we got Northern Dobruja (which had a majority Romanian population) from the Turks (via the Russians - it's complicated - long story short, even when we are allies with them, the Russian manage to nick bits of our territory, even though, in this case, they gave us another bit which they just got from the Turks as "reparations") Southern Dobruja became part of Bulgaria, specifically for that reason. We lost it again during WW1 (in retrospect, angering a bunch of guys who have been fighting literally everyone around them from 1913 onwards by randomly annexing some of their territory, then dismantling our south facing fortifications, trying to build new, field expedient ones further south and quartering them with poorly trained, poorly equipped and indifferently led second-line troops of an army who hasn't seen real action since 1878 just because we needed all the good troops to fight off the Austrio-Hungarians in Transylvania was a rather poor idea) but, despite all that and the fact we ended up surrounded by enemies with a wavering Russia as our only nearby ally (which then buggered off to have their October/November Revolution, and Romania was completely occupied by the Central Powers, but moving on), like a true Karma Houdini, we got it at the peace talks table... Anyway, to cut a long story short, we held it in between the wars, then, in 1940, under the Axis sponsored Treaty of Craiova, there was a massive population exchange, ending up with the current situation, in which Southern Dobruja belongs to Bulgaria and has an overwhelming Bulgarian majority (Romanians accounted for 0.2% of the population in 2001). Also, unlike other pieces of territory, we really don't dispute the Bulgarian ownership of this bit (save for the afore-mentioned right wing nationalists, but they're nuts). Not ours and they can keep it. Sure, Balchik is lovely and the palace we built there in 1926 is pretty nifty, but that's about the only thing we can claim as "ours"...
Finally, the flag - yes, we did have a flag with a horizontal disposition of colours from 1859 until 1866, but the colours were always arranged with the blue at the bottom, so, to my eyes, the flag you chose to draw looks "upside down".
Oh, and in the debate with Hungary about all those ethnic Hungarians living in our country, I think maybe we really should give those those two counties (also known as Székely Land) a bit of regional autonomy, because, especially in the current EU climate, it wouldn't inconvenience the rest of Romania in the slightest - after all, there actually was a "Magyar Autonomous Region" from 1952 to 1968 (It got abolished by the ultra-nationalist Ceausescu) and it didn't do anything at all except soothe some ruffled feathers. The only reason we don't is because nowadays we are just as nationalistic and we want to rub it in their faces that it's "our" country, not "theirs" any more, which is pretty childish, if you ask me.
We might be afraid that if we give them autonomy they'll want independence next and then to join Hungary, but, amusingly, the only people I heard clamouring for the annexation of those bits by Hungary, live in, well, Hungary. XD All the Székely I know (and as a native of Transylvania, I know quite a few) deplore the fact that they're used by right wing Hungarian nationalists as a club to bash Romania with and pretty much flat out refuse the idea of "independence" (they really can't survive on their own economically) or an union with Hungary, because they know they'd just become second-class Hungarians the second that were to happen. For the most part, they want to be left alone and both Budapest and Bucharest can bugger of with their silly little political games.
The border area with Hungary should remain as it is, because there, unlike the afore mentioned Székely Land, where the Hungarian population might get as high as 84%, the Hungarian population in those areas is rarely past 50% and usually below 30. Interestingly, there is a similar "spillover"of Romanians living across the border in Hungary, but somehow you never hear about that...
And let me tell you, there are a lot of people out there ready to brand me a traitor and burn me to the stake for any of the above words, because, in their opinion, anything that is not a right wing nationalistic view of things is automatically treason. *sigh* Humans. Such a silly little lot, aren't we?
Nice, but why have the historically German regions (West- and East Prussia, Silesia etc.), from which 15 million of your countrymen were "vertrieben" with some 2,5 million deaths, not been returned to the "United German Federation".
Obviously you went for ethnic borders. So here are the errors: 1. You forgot Eupen - St. Vith. The border of Greater Germany south of the France - Greater Netherlands triangle shouldn't curve. It should be as "straightish" as it is at Luxembourg. 2. Northern Schleswig is populated by Danes. Actually the Germans of South Schleswig are germanized Danes. 3. Trentino/Welsch-Tirol is populated by Italians. 4. You forgot the French Flemish people. 5. There are Basques at the western end of the Pyrenees and Catalans at the eastern end. By your criteria, Nice should be Italian, but Aosta-Susa French. 6. Corsica still French? 7. You gave Poland huge areas populated by Belarusians and Ukrainians. 8. East and South Ukraine ("New Russia") is more Russian than Belarus. 9. Budjak isn't Romanian populated, nor is the part of Bulgarian Dobrudja you gave to Romania. Transnistria isn't either 10. There are very few Albanians in Southern and South-Western Macedonia. Not even the biggest Albanian nationalist claim those areas. Part of Northern Kosovo is Serbian-inhabited. 11. Part of Vojvodina, West Slovakia and the border strip with Romania are areas with big Hungarian presence. 12. Transcarpathians aren't Slovaks.
These aren't straight-out factual errors like the above, but things you might not be aware of: 1. German speaking Swiss are a separate ethnicity, and not just a separate nation like the Austrians. And not all of Valais is German-speaking anyway. But okay, this is debateable and not a straight-out errot 2. Walloons aren't French. It's not like Germans-Austrians relation. Austrians used to be the same Volk as the rest of Germans. Walloons never were a part of French nation - they were a part of France only a few years, as much as Cologne was. Same goes for the Romands - the French speaking Swiss. Their native language wasn't even a dialect of French, but a separate language between French and Occitanian - "Franco-Provencal "or Arpitan ("Alpine") or "Burgundian". It's the same relation as Italians-Rhaetoromanians.