MMLN: Yes. I own all Mortal Kombat games from main series. 9 is my second favourite right behind MKII, maybe tied with Trilogy. Two or three weeks ago I went back to the game, because I never finished the Challenge Tower. And lools like it will take me forever to finish it. I got stuck at Challenge #251 (to beat Baraka, Sindel and Shao Kahn with one health bar) And I have spent more than three hours on it already. You have to beqt them with Shang Tsung, but I am not very good with him :-/
tinyE: I got it on a whim to try out my new computer and I'm hooked. :P I used to play #1 when it was first introduced in the arcades 25 years ago and never really played much since then, but I'm loving this. I love how they refined the moves so they aren't super easy, but they aren't overly complicated like they started to get with #3.
Still can't find a regular character though that I can totally dominate with.
I think MK X is little bit more complicated than 9, especially if you do not have Quicksilver reflexes :P The best character for domination, hmm... My issue was, that I always played with all characters, so I was typical Jack-of-all-trades, master of none :P I always loved most Smoke, but it was never the most dominating character.
I think the easiest to master for total domination, was always Scorpion, because it was always favourite character of Ed Boon. In MK9 is for single player the most dominating character Sheeva, due to some glitch, which was never patched out. But if you do not want to have cheesy wins, I would probably recommend you to master Scorpion or Shang Tsung. ST is hard to master, but he can be real pain in the ass in the hands of good player.