It was not improved, there was a sale so I think you saw more people because of that.
Anyway after playing at least 120 hours of MK9 I can only say that the online features are the absolute worst a game has to offer. I am truly amazed by the garbage that is the netcode of MK9 and guess what? Injustice is even worse. How on Earth did they managed to do that is beyond me.
Also: Netherrealm does not even talk about the issues with the netcode, they don't even say a word about it. After the announcement of MKX I really expected at least something in the matter, like "We know MK9 and Injustice was bad but we'll improve it" but no, not even a word.
All I can say is that half of the time I've spent with the game so far was just frustration because of the online mode so I simply won't buy the next installment if it will be the same shit again because I think that after the inexcusable quality of MK9 and Injustice WB and Netherrealm should suffer the financial consequences. Until the release all we can do is make our opinions heard, bombard Boon and Netherrealm on Twitter about requesting information on the netcode and if they don't respond then just don't buy the game or buy it on a sale where the price justifies that it's not the full package we were promised in the commercials and that half of the experience is broken.