Help! Receiver or preamp? Im overwhelmed...

Get an Anthem AVR.

I say this because it's cheaper than their HT processors with 99% of the same parts.  The big difference is the AVR only has RCA outputs.

So, even if you decide to keep using your Emotiva amp, you save around $1k.

Thank you SO very much gentleman! I should also mention I will be keeping the Rotel (Not that it matters). As for the budget, I'm guessing up to $1000 would snag me an excellent unit in the used market? I do not play vinyl so that will not be a concern.

As far as video I'm guessing I want to be able to upgrade to a minimum of 4k handling ability, correct? And honestly, to play music we use either a Playstation 3 and 4 for discs and use it to access the internet for music sites and use the optic connection to the receiver. We even use an old Toshiba HD-XA2 for upconverting old movie content and some audio through it as well as it has a Burr Brown Dac. Use Playstation 3 and 4 for online music, movies, games etc. 

So yes, this boat has oars and we are probably missing out on a lot! For heaven's sake, I'm still using my speakers with one set of cables instead of Bi-wiring. So I need to learn about that too...Shew, work, and family have made me quite illiterate in the HT game, but I'm keeping faith there is potential!    

Would a Marantz SR5014 or SR7012 be a good choice? Or would the audio not be as satisfying as Rotel? What older Anthem unit would be a good choice? I like music to be very dynamic and hard-hitting...

Marantz NR1510 UHD AV Receiver...What about this? Since I have an XPA 5 Amp?
 

"... What do you recommend for some killer sound..."

I’ll just spit it out and let the chips fly. A two channel system with a good pre-amp and power amp.

Edit: Sorry I didn't know I was in the Home Theater group...but I said it so I wont take it back. Just ignore me. 

I’m thinking pre-amp/processor as well Russ. No worries brother. I’m in desperate need of advice as I’m 200 miles from any pro audio places. Much appreciated!