I'd argue that just because you can't die doesn't mean you can't be defeated.
I think in terms of the class stories, the warrior comes off as the more powerful individual. But the OP asked about inquisitorS and warriorS. With that in mind, I tend to think of inquisitors as far more powerful than warriors. Politically and in terms of raw prowess with the force, I'd bet on an inquisitor over a warrior most of the time. There are exceptions, sure. The Wrath, Darth Marr, Darth Malgus. Clearly hugely powerful warriors, and in no small part because of the influence they hold. But if you look at who pulls most of the strings, and who does most of the whacked out super duper dark side stuff, inquisitors take the cake, imo.
To be fair alot of sith inquisitors have killed Darth Malgus solo
And on top of that i am fairly certain that a Sith assassin will be a pretty even match for the warrior considering, what he is capable to do. I never really felt the class story of the inquisitor matched the assassin adv. class, it felt more like a sorc class quest
So the warrior would be banging down doors killing everything in sight while the assassin would, well you get the picture.