Problem number one: there are not enough buttons for all the skills and consumables.
In theory, between Set 1 and Set 2 there are 40 possible bindings. In practice, Set 2 is very awkward to switch to. I personally can’t use it in combat, and I’ve never seen even a single video of a gamepad player using it either, so I’m assuming it’s a common issue for a lot of people.
So, let’s try getting some more buttons!
First thing that can be easily done — make the D-Pad bindable. That’s +4 very convenient buttons right there, will work nicely for potions and scrolls and such, as they do in quite a lot of other games. This should be optional, of course (just as everything else that I’m talking about), though I very much doubt that anyone uses the D-Pad for movement.
Second — allow players to completely disable Set 2 and use LT+RT for another +4 bindings. Or, another option — move the set switching functionality to one of the D-Pad buttons.
Third — the trigger buttons can actually tell the difference between a light touch and a hard one. This can be used to add another +4 bindings for each of the triggers (or even more, if you have fine motor skills). It’s a little hard to explain, so here’s a little mock-up: https://jsfiddle.net/988Lp7av/
Use the right trigger on your gamepad to move the circle along the bar to change “skill sets” with different amounts of pressure.
Fourth — macros, or skill chains. I.e., binding Surespell and Quickcast to a single button, which, when pressed, will cast the buffs one after the other.
Fifth — and a little bit of an offtopic — change some game mechanics to reduce the amount of bindings players have to use. I.e., Necro’s corpse potions are a complete waste of a button. There is no challenge involved, or strategy, or anything, really. Just make Gather Corpse and Desinter better, or reduce casting costs, or something.
Problem number two: mob targeting sucks.
Without Target Lock, the right stick pretty much doesn’t do anything useful. Not really sure if anything can be done about this. Any ideas?
With Target Lock, on the other hand, it is actually possible to pick a specific mob… if you have 5 minutes to spare doing that. To avoid lengthy descriptions, here’s another mock-up of an idea to help with targeting: https://jsfiddle.net/gka6aueo/
Use the right stick on your gamepad to pick a target, then allow the stick to quickly snap back into its resting position. It’s wonky, I know, but hey, it’s a start.
Problem number three: skill targeting is… kinda OK, actually, but could be better.
First, it is very hard to see the targeting reticle in some circumstances. I.e., during party play it’s effectively invisible under all the mobs, effects, nameplates, etc… Consider making it a translucent 3D pillar, or something like that.
Second, some aim-assist would be nice to have. There’s a reason why pretty much every modern FPS has aim-assist for gamepad players: targeting with a stick is difficult and slow.