What level is the merc? If it's lower than 90, may hire a new one that's higher than level, idk if you can hire same level as you, but if 88, hire 89, may get 1 more strength.
However, i can see giving up the cleansing aura may be a loss, but andy's is a super solid helmet for merc. Maybe the fire res penalty may hurt the merc a bit, not sure where you run, but probably will be even better with that one on.
And with the huge damage increase, and andy leech, will leech lots of life.
To me it's a no brainer ^^ That's from jagged alliance 2 ^^ A very weirdo mechanic xD called "perko" ^^ Which is kind of lazy and a super weird character ... when you give him an item to repair, he says "this is a no braineerr" .. xD if you attack him, he'll say "when i get ya, i'll fix ya!!" xD And runs at you with a knife xD is unarmored though so he is easy to kill ^^ But kind of just not worth it, town will lose loyalty and you lose money, just leave him be is the best thing. Use own mechanics instead.
So there ^^ Random gaming piece of advice for the day ^^