Nearly all of the majors have really been pretty merciless with their partners.
Mergers are a nightmare. I'm sure everybody has thought about it but half of the reason that airlines like US Airways find themselves in this position is that previous mergers have not gone entirely well.
Scope is a pox on humanity. It's corrupted the market.
They want other branches and roots to flourish. I actually take this as a sign of Delta's commitment to Cincinnati over the long term. Cincinnati as a hub is not going away, and this is just tweaking it to make it more effective.