I like the lockdown timer. It means that the game doesn't go on for 30 minutes even though the attackers aren't going to get past the second set of objectives. I think it could work a little better though, it should be harsh on the first objective but get more relaxed as the attackers progress. <Snip>
I also like the idea of the lockdown timer as I'm often on teams that refuse to attack and the lockdown forces them to get their act together and advance.