Playing this on a gamepad is indeed impossible. The lack of mouselook, combined with the sheer number of functions needed to effectively play, the need for accuracy when looting bodies/opening doors, and the need to tab out for a variety of reasons (map, TS, finding out why you have aids) makes it near physically impossible. Drag and drop especially would seem really problematic, not to mention that you'd be at a severe disadvantage when precision aiming means so much sniping. I can't imagine doing it any other way. Even the cheapest mouse is better than the alternative.
On a different note, for those who haven't heard me recite it on TS, it's possible to carry two rifles:
1.) Take the rifle you're carrying out of your hands so that it's on your back.
2.) Find the second rifle you want to pick up and mouse over it
3.) Click "Take (whatever rifle)" when you get the prompt mousing over it.
4.) ???
5.) MURDER
This puts the second rifle in your hands. You can use the "punch run" while having two rifles by running with your rifle raised, then clicking "use bandage" in the inventory screen. Your guy will switch to rambo mode, with the rifle you're carrying going into a one-handed carry, so you can fast run like you would if you had nothing in your hands. Downside is it can bug out your scope to where you have to relog. The other downside to carrying two rifles is that whenever you loot anything or use any other item in your inventory (or drag drop the other rifle to your hands), you'll drop the rifle currently in your hands, so you have to repeat all the steps above.
Yeah, it's a cheap glitch, but partially balanced by the fact that you can't do it effectively in combat, or while you're looting, or climbing ladders, or while you're doing any other number of functions you constantly have to manage. It's great, however, for grabbing an extra rifle for a friend as loot delivery.
Watch out for the highrise buildings near cherno. There's a weird bug where vaulting will phase you under the floor and you'll be stuck there until you can find a way to glitch yourself out. I think relogging might fix it, but if you run and vault around for a while you'll exit out somewhere. No guarantees you won't just get gibbed though. Had my long range scope mosin poof underneath the floor while trying to climb a ladder, glitched underneath the floor... Trying to get near it got me within a foot of grabbing the thing, but an invisible wall blocked it. It was like the game was punishing me for exploiting the inventory system. The game can kiss my ass though. I refuse to believe it's realistic that you can't carry two rifles at once, or at least break down one of them into component parts and carry it in a gigantic mountain backpack.
EDIT: And the sad thing about me getting lost is that I've been playing the mod since a month or so after release, and even when I thought I'd found where I meant to go, I ended up 4000 meters off. Still, I ended up closer to NWAF than I thought I was heading. Apart from the coast, the whole damn game is samey looking forests and fields and I spent the entire mod relying on the magic map markers GPSing me to where I wanted to go.