Best upgrade path?

If your current system has what you've been looking for, then why upgrade? You wouldn't wanna get upgraders regret; parting out a system you enjoyed, then once its gone, kick yourself for parting it out.

I hear a little talcom powder can help the itching though. :)

Seriously, take my advice for what its worth. Keep the system if it truly makes you happy. No need to upgrade until an upgrade is needed.

What do you want more/less of?

wait for the itch to pass, or get into vinyl...where you'll have a world of issues other than upgrading your great components.

I'd start with speakers first.
My suggest: Dump the Totems for whatever you can get for em (I seea used pr goes for like $1500. Take that money, throw in a another $1K and get the Tyler's MTM design, Either floor stander or the lower priced book shelf model.
Now work around that. Next step is pick up a used tube cdp, for under $1K.
For amp, I'll leave that to someone else. The Tyler MTM's need the juice though.

Perhaps a little more bottom end, and a little more"oomph"
to the presentation. It's hard to single out what I'm looking for specifically because I haven't listened to
many other systems.

Your system sounds wonderful! If you’re not sure what you seek, save yourself some money and be happy with it. If you have the itch, and need to upgrade then consider these ideas:
(1) If you live in your own home are you using two dedicated circuits (amp/CDP) with high end AC outlets such as the Porter Ports for example? That would make a significant difference in detail, transparence, and perhaps more bass slam.
(2) You never said what type of interconnects and speaker cables you use. An upgrade might be desirable.
(3) Plinius makes several amps that have the ability to play class A/B or with the flick of a switch solid class A. Believe it or not the class A is an improvement. That said, I should know. I own a Plinius 8200, SA-50, SA-100 and SB-300.
(4) Have you done any sonic room treatments?

Best regards,

"...get into vinyl...where you'll have a world of issues other than upgrading your great components."

Chuckle, chuckle. Good one. Profound words, indeed.