i wouldn't put a cap on it because all that does is make people feel like they have to write that much for their app to be considered acceptable. in my years of modding i can count on two hands the number of apps i've received that had personality sections longer than 1k and most of them actually weren't padded with a ton of filler. i've found that most people tend to end up in the 500-800 word mark if left to their own devices.