I still think the “best” way to “buff” eles would be to add a new trash unit that synergizes well with them.
I made once concept idea of a “chariot”, which is a trash ratha with very low HP and selective bonus damages. I think it would optimally synergize with the eles as it is frankly the total opposite: Needs attention, fragile, fast and revarding when you manage them right. Also with only costing wood there is no res overlap and it needs not much economy to be added.
One of my Chariot Designs can be found here
Especially with the high bonus against monks it can possibly compensate for the Elephants weakness, but in an interactive way that requires skillfull use of both units.