Slot perk
In my opinion, an extra perk slot is needed but only if you divide the perks based on what they do (gen perk, aura perk, exhausted perk) and make sure that out of 5 slots only 4 can use the same type of perk (so as not to have combos that are too strong but more variety in the builds).
(or an extra slot only for utility perk )
or even 6 slots but make other changes that limit the maximum speed that a generator can reach and healing speed that must reach a certain cap. (always with a maximum of 4 perks of the same category).
Comments
I think the current limit of 4 perks is fine.