Most builders spend (read: waste) resources and time making complicated traps when a simple bomb or two can put it out of commission. I find that a simple pit does the trick when making traps. The pit has to be deep enough for bomb/explosions to not effect the base at all and now your base is now bomb proof. Make no blocks in front of your door, that way, any bombs thrown at it would just drop down into the pit. Although an alternate method of entrance would be needed for fellow teammates, that's nothing that couldn't be made quick and cost less resources then a trapping spike pit or saw pit or any other type of trap. Also, unlike these traps, pits are bomb-proof. A pit combined with a layered wall could just make fun an unstoppable base. You can't even bomb the base as a knight, and archers bomb-arrows just make easily repairable damage.