Any Home Theater Experts here?

My home theater setup right now is a Sony DA777ES 5 channel receiver that I'm using as a processor; and it is also driving my two rear speakers. The center speaker is being driven by a Bryston monoblock and the fronts by a Gamut D200 amp. The front speakers and center are Verity Parsifals. The surrounds are Mirage Omnis. My home theater is also connected to my Sonic Frontiers Line 3 preamplifier which I can switch to bypass mode whenever I want to listen to two channel.

My question is: I can understand that for 2 channel listening with a seperate good preamp, I could hear soundstaging, detail, musicality etc, but what should I expect the improvement be if I replaced my Sony receiver with a dedicated home theater processor like the Outlaw model 990?

I would be using it mainly for watching movies since I only listen to 2 channel when listening to music. I'm using my Sonic Frontiers preamp for 2 channel, which I assume is better than the Outlaw in this application.

Experts, pls. advise on if it's worth replacing my Sony receiver/processor for a dedicated home theater processor like the Outlaw model 990. Will I enjoy movies more, or not really?