I think this question plays into the idea of a "fuse".
We do a lot of rock crawling and would totally love to run a front locker, however it would change our fuse. Right now, our fuse, or first thing to break, is traction. Simple enough, we don't have the bite. For the wheeling we do, that's ok, as there is generally more than enough traction with just a rear locker. (not always, a front would totally be awesome). Add a locker up front, and our fuse moves. When the first thing to break was traction, and now we fixed that, the fuse moves to the next weakest link. That may be a CV, the stock steering rack, maybe even just the TRE's. Is it super simple to swap steering components and carry spares on the trail? Sure, done far worse a thousand times. However, as we generally wheel alone, or with one other rig, keeping the rig intact, vs fighting repairs, is the name of the game.
If youre keeping a smaller tire (we are on 37's), aren't heavy in the throttle, and just want that extra aid, I say go for it. But if you plan to run bigger, or harder, realize that changing to a front locker means something else will give first. HTH