If mainly movies are you deal, then the S150's should serve most just fine, and do well in low ceiling applications.
As for Oppo bypass, fer chits and gigglies, you can always try tinkering with bypassing the external pre/pro, going straight to amps, yes. But, you will easily find that you'll find no significant upgraded mid-range, top end, or open sounding upgrade doing this with your M&K S150 series, assure you! Plus, you can guarantee a downgrade in ultimate dynamics and processing options, plus convenience and ergonomics. Stay with the processor (then you can also A/B compare till your hearts content, FYI).
That said, I think the EQ in the anthem and overall refinement it offers (gunna be about as good as you'll hear through those midfi HT speakers -yes, Midfi..I sold em many years), will do more than fine for your needs. And you WILL NEED the EQ in all but the most ridiculously over-sized, high ceiling domestic home spaces, if you care about flat accurate sound and response - Absolute necessity, yes.