Definitely an improvment over the previous one..
There is lots of good stuff for this game;
+Tech research is definitely well improved over the previous one, it adds more value than any other aspect of this game.
+Combats are more PG style, (encirclement, breakthru, etc. factors & Leaders)
+Diplomatic relations and superb historical accurancy let you drive your way.
+Goverment dudes are adjustable which effects nation performance greately.
+Amazing replayability & modability value.
+Living and breathing world around you.
And there is plenthy bad stuff also;
-Air forces organization is somehow tiring to keep up with. Arranging them together and giving missions continously is wearisome.
-Diplomatic relations are a bit buggy. Agreeing alliances are more than impossible.
-The major nations are non-annexable making USSR undefeatable. (Means capturing Moscow as Germans gives you nothing)
-Naval combats are happening very quickly unlike the real ones. Also Submarines are nearly useless because of their unrealistically low morale.
Anyhow, there are lots of sites that offer lots of stuff like, improved icon graphics, more realistic stats, sound effects and scenarios. Also newly released patches fixed lots of bugs already. It is a strong candidate to be a masterpiece.