At first i wished i'd waited for dw5. upon playing though i see as usual it's full to the hilt of amazing content!
The battlefields are improved over dw3, but they won't blow your socks off. The a.i. is about the same though they seem a lot more aggressive. Lu Bu will pwn joo, so just expect it. heh heh.
The new stage designs are similar, but just different enough to keep you off balance for a while.
The bottom line is -typical koei fare- it's very similar to the previous title we loved, but with just enough tweaks to graphics, costumes, and stage design to get you coming back for more.....yet again. argh! :)