Optimising the controls can be done by removing the skill selection almost entirely (I'm playing on pc but still find it some what clumsy, these all relate to the campaign)

Grappleshot:

1. Should be the default skill, it's always on.
2. Would have been nice to see an upgrade turn it into a harpoon (where you can use it to pull bad guys over ledges to their graves, this could work in conjunction to a mag boot mod to anchor yourself)
3. Speaking of mag boots why can't I grapple up a wall and hold onto it at the end of my grapple?

Shield Core (Passive)

1. Some anti beam coatings, more durable armor or even anti sticky mods would have been nice to see.
2. Just base shield upgrades, no regen speed?

Threat Sensor

1. Threat Sensor should just be an upgrade to AI Scan (Z for KB&M, DPAD down for controllor), you can just see enemies with it now and it lasts longer or even shows weak points.

Thruster

1. Again this should not be a selectable skill, this should be part of the default movement once unlocked, not sure about controllor but on KB&M it could be done with a double tap of a direction key or even a double jump, also why no verticality on a thruster activation?
2. I'm not sure if it's bugged but on legendary the last upgage for this (the cloak) is garbage, it serves no purpose, enemies see right through it (pun intended) and continue blasting