You're not going to start one of those "my class is nerfed" things are you? Cause players of every class go on about how their particular class in nerfed in some way.
I've played a lv 50 Vanguard, Marauder and Gunslinger. Was close to getting my Assassin to lv50 and was working on several other classes, I'm sure you've seen the screenshots of my toon list.
Whether you play a sage or whatever is irrelevant cause each class has their own strengths and weaknesses and the PvE stuff is pretty damn simple to take on, even without your companion. I've done it plenty of times, especially with Silvana cause by the time she reached lv50, Vette became useless because she still has very low level gear so she goes down instantaneously leaving me to take on a mob by myself with my Marauder and sometimes a patrol too when I get sloppy.
After playing through all of these different classes I've managed to figure out what makes each tick and how to best use their abilities, even when the odds are against me. My Sage may be sitting on the fleet at lv10 with the Rakghoul plague infecting her neglected ass, but I think I've played through enough of every other class to say that the whole "this specific class is nerfed in some way" argument is stupid.