The fighting system is better, there are a couple additions. It's a lot better than Deadly Alliances IMO. There are plenty of combos, depending on the character. Konquest is a chore but you need to go through that and the krypt to get what you need. Some familar characters rejoin while others are cast off. I think it's a bit faster than the first. I play online through xbox all the time.
Offline, combos are pretty easy, you have to delay everything a tad online because of lag but when you get good theres really no problem. Combos that require timing, like juggles, take even more skill but it's still not impossible. I don't know anyone who would type out their combos... if you can wipe your ass then you can do combos in MKD