100% agree with @Furious_Fighter1 , it depends at what tier of war you are in. However, I have seen defence/offence recommendation graphics before (see below). This is all subjective and is just opinion though. What works one week, might not work the next time. It all depends what counters the opposite alliance bring.
IMO AW defenders depends more on the tier of War. At lowest tier, Even BPCW can alone get you 10-15 kills on boss, however at highest tier, even korg wont get you kills.