There are a few 2kro keyboards that have a really good matrix, and will be fine for gaming, but in general 2kro is just not enough.
I would not use anything less than 6kro (of essential keys only of course) for gaming. In fps games it is very easy to have to hit 5 keys at once, and in sc2 you spam so many keys, that it is inevitable to have ghosting/lockups/errors on a lesser 2kro keyboard.
The main reason I ever looked into mechanical keyboards, is because of how badly 2kro was hindering my ability to play games at the level I desired. If you are a casual gamer, then you probably do not care (or even realise) if you lose a game because your keyboard did not accept your command, but for me this is not acceptable. Someone might counter with "X pro player uses rubber domes and they are the best..." but these pros play on what they are used to, regardless of how flawed it is.
Conclusion: IF you want your keyboard to give you the best performance (as it should), then do not listen to people saying 2kro is fine. BUT if your 2kro keyboard can accept 8 of the keys you want it to at the same time, this will also be fine. On most of my 2kro's the problems occur with pressing 3+ middle keyboard keys, or 3 keys very close together.
Or you can use the teensy device to make it NKRO.