Maybe games are too fast because siege is weak?
Just a theory, but a lot of the best siege oriented champions haven't been meta in ages. Except perhaps Xerath. The kind of artillery mage with high wave clear who can keep their distance and either push people out of tower safety or hold off a siege against their own towers.
Maybe games would last longer if you had more champions like Ziggs, Lux, Anivia etc holding back minions waves and stopping teams from committing to tower dives as much.
There are less and less ways to defend a base these days. If they are already ahead they WILL break in right through the front door and vice versa if you're on the winning team.
The AP item update might help though.