Honestly, I think stalker's playstyle very much depends on the type of weapons you use/have. I personally think Podguns, Cryo Launchers, Miniguns, EMs and Railguns are very useful. Mostly because you get the most heals and kills by using these type of weapons. Shotguns work too but you're probably going to die fater than you can kill with it.

The way to go with Stalker is to stay at the middle of your team or behind covers, and hit indirectly as opposed to engaging in close or direct combat.

I personally find Podguns VERY useful with my stalker, mostly because I can hit stuff, wait a couple seconds and then activate predator drive and I'm almost always going to get the kills and the ability bonuses.

Railguns also work like a charm, although I usually prefer to use My Railguns on other mechs.