Yeah there is no way you can exclusively use firearms IMO, there just isn't enough ammo.
I think it's way too early to make any judgements about farming right now. Play a full 70+ hour game then decide.
Yeah always have an exit plan. I actually bought all the parkour perks for once and did some crazy jump falls to escape one situation.
We didn't want it to be OP and make everyone feel like they needed INT to play the game, or feel excluded from Drones. If it gets much better it will feel like a must have. Right now it's ok to haul a little more loot around, but it gets in the way so it's kind of a trade off which is how it should be.