Yeah, I don't see a reason not to require mail-in ballots (which everyone should be allowed to utilize) to be postmarked a week prior to election day (or some other +/- timeframe). If you are proactive enough to consider mailing in your vote, you've also probably been proactive by having already determined who you are going to vote for.

Edit: it’s a bit like in-person early voting in Texas. Early voting stops around a week before the election, so if you can’t make up your mind by mid October, you’ll just need to vote on Election Day with the rest of the peons.