I fully support this, and was about to post something similar myself. My one caveat: this change, if implemented, should go in simultaneously with an across-the-board increase in regeneration rates.

Given that move/mana/hp additions only happen "on the tick", a character that would have received X under the old system will now receive anywhere from 0% to 100% of X, depending on what percent of the hour they'd been asleep. Even if I'm not trying to do any "tick timing", this change will reduce my overall regeneration rate since I'll no longer receive 100% of the benefit from the first tick after I go to sleep. If I'm sleeping for 10 hours then that isn't a big deal, but if I'm only sleeping for an hour or two it can be significant.