It comes down to a trade off of sample size per epoch vs stake liquidity. Allowing the option of freely moving around more frequently can only be a good thing from a staker’s perspective. If it were every day, I could see how that would no be enough sample size and stakers would have to analyze performance over say many epochs to really decide if they wanted to jump. So we want some level of sample size in the epoch data. Moving from 10 to 7 certainly doesn’t hurt the sample size.

Can anyone think of a drawback to lowering it? I haven’t researched what goes into operating the staking contract from an administrative perspective. Does someone from 0x have to send just one single transaction every x days to trigger the epoch change? Or is it more complicated than that to operate?

There may be UI/UX considerations in the staking portal for dramatically reducing or dramatically increasing it. But those certainly would not come into play when reducing it from 10 to 7.