Some of the bugs are present, but in general, the game has been improved. There are free play maps, most of the bugs are gone. Still, the AI is somewhat stupid... It usually lets you take control of the focus points (double damage) which practically is a "I win the battle" button.
Kinda runis the game, but still, the textures are great and the units are very beautiful. Especially the female ones. However, the big eyes on some units do ring of some manga style chars, but still, it is a job well done.
EDIT: And of course, let's not forget that HOMM derived from King's bounty 1

So in general we should compare Disciples 3 with KB1

There was already such a topic on the forums. KB1 was launched in 1993 by the company of the very creator of HOMM - John Van Caneghem, and was used as a standpoint to create HOMM1.