Mongo makes agg management too easy. Be it for end game or pocket teams.
What I would suggest is to add a 15s local cooldown on it. It won't change much in PvP as the hot part has a 22.5s duration. The effect in PvE won't be huge but might add some - read tiny - challenge.
Can't think on anything else to change in enf tools that could be done outside the re-balancing. Do you have any other ideas?