I also love IG100 but I stopped him at 6*, Gear VIII and level 76 until I reach 80. The other Droids simply are beater so I (must) level/gear them first. St.Han works good as a Placeholder until I can upgrade my IG100 to his full power.
Hope he will get a Taunt or the developers will rework either dodge (Dooku) or some character abilities. IG100 Offense Down miss a lot of it's potential because it can’t overwrite or negate Offense Up... And we all knew that Arena is full with Characters that gain easy Offense Up either on Basic Attack, Dispel or Evasion thanks to Leader Ability.. Afterall we see way more Offense Up than Offense Down.