Sektors leg lift only gets useful in the corner but not by very much. You should not be using leg lift as a combo starter because it is impossible to hit confirm into teleport uppercut. The 1, 2, 2 string is good for catching people with an overhead because most people don't understand that it is an overhead in the first place or it just helps vary your offense. I always cancel the 1, 2, 2 string into missile for the additional meter/block stun.
The thing about Sektor that people don't seem to understand is that he is not very combo intensive. He is essentially the Dhalsim of this game, he pokes from far away and pokes hard. Every time you push them full screen they have to go through Armageddon to get close to you again. I like to do up missile (on them), straight missile, up missile (in front of them), straight missile, flame. Depending on how quick they approach or don't approach you might have to change this missile pattern. When you land a flame you seem to be at slight advantage which gives you the opportunity to try and push them away again or run his limited set of frame traps (something I am still working on).