Are the 3 campaigns easier than 2? Because 2 was brutal, I eventually gave up. Most of the missions were winnable but would take me over a week just to do one. It got dull and repetitive chasing all the AI heroes around the map. I hope 3 has a difficulty setting.
Edit: Just downloaded the homm3 hd patch/wrapper and it is amazing. The game looks really good. 1920-1080 made everything a little to small so I got a very close to 16:9 ratio at 1360-768 and it looks great. Sharp but not too small. So far I have only launched the tutorial but I'm excited to dive in tonight. Again I just hope the campagins are toned down from homm2. Just a tad too hard imo.
The early campaigns in 3 are pretty easy, even on the highest difficulty. The later campaigns... not so much. They can all be done, but they'll require a reasonably good understanding of the game, and sometimes also require two tries so you can learn the map on the first try. On the plus side, there are difficulty settings for the missions so you can always knock the difficulty down if you get stuck.
I can't compare with heroes 2 campaigns because I have not played that game since something like 1997 or 1998... my memory is just too fuzzy.