I like the concept.
EMP Grenade;
make it grenade which just explodes once, that way timing and aim is more important instead of just throwing it somewhere, anytime, like motion sensor.
The EMP shuts down deployables and Phantom’s shield for 4-5 seconds, disables mines and scrambles vision of players for 1 second , working a bit like a weak flashbang for 2 seconds.
Hack Tool;
Just permanently convert a deployable, must be used in melee range and takes 2 seconds to convert, the device will then “reboot”, being active FOR Hacker after 1 second.
The converted object will disappear when the original deployer uses the ability again, this will use the internal cooldown of the ability. Will work on heal/ammo station and turrets(will have to sneak up on it)
This will allow the team or Hacker him/herself to restock ammo or health for a few seconds.
Another option would be hacktool at range but with quite a long, static channel, so you are are very vulnerable while hacking.
This will make Hacker a great supporting engineer, not real damaging abilities but debuffs for the enemy team.
The combination of EMP grenade+Hacktool would make it possible to disable a turret, rush in and hack it(within the 4 seconds)
The 1v1 concerns; EMP nades can be used to debuff the enemy’s vision (a bit) and with smg-swapping would be
Weapons wise i think it’d be cool to give Hacker 2 secondary weapons, not dual wielding them per se, but say, the smaller smg’s and the powerful handguns, so Hacker can empty an SMG, switch to next SMG or choose to go for hard hitting handguns. While this is still powerful enough, remember that Proxy can do this with a primary SMG/secondary SMG already and has easy to use proximity mines so this should be fine.