The only toon in guild shop I haven't maxed is Gamorrean Guard - and he's firmly at 70/100, just in case I need to finish him "quickly".
So, what else to spend currency on, indeed. Between an average of 200 coins per day from guild activity (often more), and the coins from the raids (6k per week at the top spots), it takes only two weeks to have 50 Droid Caller components. Three weeks if you're low-scoring in the raids.
I'd call it fine. Especially as you get to pick gear unavailable outside of raids.
Off course, don't go buying gear you can farm...