Had the Iron Guard never risen to power in the Kingdom of Romania and had the country remained blatantly liberal like in the years before, I'd say the fate of the Second World War would have been a different one.
For starters, Romania was where Nazi Germany got all its oil from, cheaply, during the war. Had the country not joined the Axis and instead continued to play buddies with Paris and Moscow, it's very plausible that Germany would have had a much harder time in "conquering" Europe. The ramifications of the Balkan theatre would have been vastly different - with Greece, Yuogslavia, and Romania up against Hungary (whose army was peanuts at the time), Bulgaria, and Italy, it's safe to say Hungary and Bulgaria would quite frankly fall in a matter of weeks, leaving the Italians alone on the front against a couple of nations they've struggled against in the OTL World War II, as well as Romania.
Supposing a Molotov-Ribbentrop Pact would have existed and supposing the Partition of Poland did occur, and supposing the French fell as easily as they did, Germany would have had the time and the capacity to help the Italians out, but not easily. All in all, by say 1942 without Soviet involvement, Romania, Yugoslavia, and Greece would fall, but if the Soviets had gotten themselves involved we'd be looking at a much more progressive Eastern Front.
This would open up room for the Western Allies as well and Normandy would have happened some time earlier. If they'd have even considered it. Judging by how Italy struggled, they might as well have invaded Europe through Sicily. We'd be looking at an entry in Germany through the south and east, as opposed to a western attack.
As for the post-war situation, one would have to say the Soviets would get the better part of the deal.
That's just my take, I invite y'all to post your own as well.