Being droid constrained means you are doing something wrong; credits should really be the bottleneck.
The problem is that you are unlocking lots of different characters (hopefully nlt from chromiums, as they are the worst way to spend money unless you want to spend thousands) instead of focusing on a handful of characters and getting them to 7 stars before going after others. I focused only on my arena team, and have finished GW every single day, so I think it's a false dichotomy to say you need multiple areas. Raids do benefit from specific characters, but unless you are at the stage where you're constrained by raid gear (and you aren't), those raid-specific characters should not be a priority.
