I think that the idea can only really work if there wasn't re-spawning. If each side starts with 128 troops, and they're all you get for the fight, suddenly all the tactics become important. Saving allies is essential, as if meeting objectives. That's why the systems work for real military forces. If a soldier could go on a rampage and then respawn, we wouldn't have structured combat and we'd have the same problems in real combat as in online combat. You can't really enforce discipline in a computer game. So I think finite lives, everyone working together for the greater good, is the best way forward...but it'll never happen.
I would like the idea of a mode where the match ended by killing the opposing team, as long as each team was able to revive its own members. So there would be strategy in keeping your "medics" alive and eliminating the other teams medics. That way there is at least a chance you can get back into the match and you might not die seconds into a match and have to wait until the entire opposing team was eliminated, or for some other match condition to be completed.