I still keep exclusively using buccaneers at townhall4 cause any other unit up to thief isn't that reliable as this basic unit. and this could ruin the game experience/make it boring. granted, there is also just "BARCH" in another game but still, just relying on one unit doesn't cut it in the long run. That is all arrrrrr!
I balance my troops, usually, 4 brutes, 5 thieves and 14 gunners. Works most of the time. but composition of your troops is less important then choosing the right target!