I really miss when bans and picks did not have to be locked.

And I can't think of a reason the forced lock was added. Especially since if you're tabbed out of your client, you get reminded to lock only near the very end of each phase. And even more so since the 10 bans were introduced!

The single excuse I've seen for it is that it "shortens the champion select phase", but I'd rather have a champion select phase longer by a few seconds because one person waited their timer out, or even simply failed to notice it was their turn to pick, than being thrown back into queue and waste a lot more time, possibly several times in a row.