[HoneyBadger]

I'll agree with Jazzepi that the interface is clunky.
I'll add that the lack of a strong AI-and moreso, the lack of a programmable AI-is a big downside for me. Even the combat AI isn't that strong.
I know it's not a big deal, and that I can play my own music, but I really wish it were a stronger aspect of the game, since the little we have with the game is tantalizing.
Staring at a more or less blank screen, reading the same 3 or 4 tips each turn, just plain sucks. Again, I know I could go do something else, but I'd rather have something game-related and interesting to look at.
The nations that come with the game, while multitudinous, still downplay the same parts of the world that are typically ignored or downplayed in other games, namely North and South America, Russia, India, Asia, Australia, Oceania, and Africa. Where these areas have nations, they are usually very typical, being based on China, Japan, and a generic African tribe. It's very Sweden-centric, if that can be a word. Being an American, I ofcourse understand the desire, but it's still something I find faulty. The only one that really stands out as different is the one based on India, and that draws heavily from Kipling, who was English.
Forgeable items really should be Age specific. That just makes sense.
There's no graphical reason (although I can understand processing requirements) why units couldn't and shouldn't have more than 2 images. Even if it's optional.
Some of the ways stats are handled seems arbitrary and needlessly generic. Hitpoints, for instance-it would make more sense to me if they were linked to size. Size itself, being of such importance that it has various game mechanics built around it, seems very limited at from 1-6. If hitpoints only went from 1-6, you can probably see how limiting that would be.
Another thing that irks me a bit is how certain aspects of the game are very independent from standard fantasy tropes, while others seem quite generic-eg. we don't have even Tolkien equivalent elves (which are more original than the average fantasy elf), but we do have D&D equivalent dragons (which are-if anything-less original than average).

Now, all of these things I've already addressed, at length, in other posts. Sometimes more than once. So no, I don't think Dominions 3 is perfect. I do think it's a fantastic game, that easily lends itself to being a hobby-and a very inexpensive one, which was the point of the thread.