@Fher I like Ahsoka as well. I have her 6*, max gear for lvl 67. I use her with Ima Gun 4* (lead), Lumi 7*, Jedi Con 6* and Mace Windu 7*. I hold a #25 - #50 spot in arena with that team.
She has nice stats, except for her speed. Higher gear and star levels really help her crit, which actually makes her special heal a good number of times when used. The counter attack chance from Ima really helps her get more attacks in, which means more damage and self heals.
I think she is good, and she synergizes perfect into my team. As others have said though, there are 'technically' better damage dealers, like Tie Pilot. I use Mace, and he's no FOTP.
Anyways, I think a lot of the dislike for her comes from her low speed and only good/decent damage, but people disregard her utility. The teams today all seem to be about high speed, big damage. She brings a good amount to a Jedi team I feel.