I recently reinstalled Vine after noticing it was almost 1.5GB. Insane. I have had to do this several times, too. Instagram has reached 300MB a few times as well. Messages reached 1.2GB on my iPod Touch, even though I had no messages, I deleted them all. Luckily, my main device (retina mini) hasn't had this issue yet, right around 20MB.
I really hope that Apple will implement a way to strip apps of all this junk within Usage settings or something. Like, there could be maybe a few buttons, "Clear all cache" which would delete everything but the app. Then another button that would delete all the.. Extra, more unnecessary stuff, but would preserve your saves in a game, for example.
I have sent feedback to Apple as an "Enhancement Request", even though I'm not exactly sure of how possible implementations of a feature like this would be. I'm assuming it can be done still.