Don't know how relevant this is to the soldier vs. sentinel discussion, but I just landed in a game where someone played an unusual, no-flamer soldier build. This was mostly a melee build - which took a lot of finesse for closing distances and dancing around big units- complemented by a wraith and inc ammor to prime + detonate (carnage too of course). I assume bloodlust was specced for melee and speed. Interesting wrinkle, the kit used armor comparments, and at the beginning of non-obj waves, he would use a missile to get the bloodlust stack going (didn't really aim for killstreaks either, and this was on glacier, so def not scoremongering). The guy did really well with it, this was on Gold vs. Reapers, so the map helped him, though I guess there are better factions to play with as a melee kit.
So, if you don't like to flame everything, or would like to inject some diversity in your vorchas (and have the engineer specced for non-melee), this is an interesting build that seems to work on gold; not easy to pull off, but looked lke a lot of fun!