Ok, that is a significant change in room size. Sounds like you went from a 12x14x8 room to a 25x25x12 great room! Yeah, I can definitely see the M22's and VP150 struggling to fill this with the inadequate power out of the Denon. Even the Outlaw sub won't be able to fill this massive space!
Simply upgrading your AVR is not likely going to cut it and at some point you are just going to introduce distortion to your speakers if you are trying to replicate "volume" levels experienced in your study.
You can approach this piecemeal and do one upgrade at a time depending on budget. Definitely your LCR's should be bigger. You have the space to go full tilt on M100's and a VP180! Then for sure you are a candidate for $1000 AVR's outputting at least 125wpc. I would honestly look at an Emotiva MC-700 and ADA 5-Channel amp combo (or an Emotiva A-500/XPA 5) if you don't think you will be doing ATMOS. And definitely a sub upgrade. 350W amp is nothing compared to an 800W EP-800! (Though even the EP500 and EP600 would be improvements).
