What should I expect moving from MM to MC?

Thank you @lewm . Your response makes sense. I am going to look into the pre-amp first with my current setup. From there I can dabble with the cartridge, if necessary. I'll look at both of the recommended ones.

Thank you both for the responses. The Denon amp is set up for MM only, but I read that I can use an MC High Output cart with no issues.

A few points/questions:

1. What I like about the Sumiko carts is their broader frequency range. The RP-500M's can reproduce frequencies up to 25khz. Some of the cartridges out there are limited at 20khz. While I've never been "tested", I have very sensitive ears and believe I can pick up frequencies over 20khz. So to this point the Otello may not make me happy but the  OC9 series looks like it would.

2. So to get to the bottom of it, for more warmth and fullness am I chasing the wrong animal in looking at a cartridge upgrade? Or would I be better served with separate pre amp and amp? or even speakers that may reproduce the mid range better/fuller?

Again, thank you. I am learning a lot here.

@tablejockey I like the idea of the pre-amp. A friend of mine recommended this, as well. Do I then route the pre-amp into the Denon amp phono inputs? Or other?

Based on all the feedback, I went ahead and ordered the Schiit Mani 2. I'll start there. It gives me  the option to move to a low output MC cart if I want to in the future.

I really appreciate all of the replies. I’ve learned a LOT, just from this one topic. Many of your responses have inspired me to do a little more online research, which leads to more investigation and research. All in all you’ve set me on a good course. Let’s face it: I’m a budget hi-fi/audiophile. Some of you have cables that cost more than my entire setup.

I’m starting with the Schiitt pre-amp that should arrive here in a few days. I’ll play around with that and listen to a lot of vinyl to compile my impression of where I am at that point.

If necessary, I’ll probably dabble with a better cartridge, hopefully something MC so I can hear what all the hubbub is about. My Olympia is a $200 cart, and one website said I should probably pair my $1,000 TT with something closer to the $400-$500 range. Many good suggestions in this post worth looking into.

Finally, and it probably won’t come to this, but I can always upgrade speakers. I mean, who can’t (or doesn’t like doing so)?

I’m also learning that my misconception on the frequency range of the cartridge isn’t as important as I had originally thought. 20hz-20khz covers what I can hear. So it comes down to tonal qualities, fullness and clarity. This opens my eyes to a much broader range of potential upgrades in cartridges.

Thanks again. I may be old, but I’m still learning.

@ronald_p Great point about the used market. Definitely  a way to upgrade and save some money at the same time.

Mani 2 has arrived and works as advertised. I'm going through my albums on different eras and genres. So far I wall say there are notable differences, including the ones I was hoping for: broader soundstage and a boost in the previously flat mid-range frequencies. Vocals and solo instruments have come forward and the oomph of the bass with the fuller mid range have filled in the gaps. Thank you all for the recommendations.

I'll still go through a re-listen to most of my collection. Two albums that I love but just didn't sound right were:

1. Asia (Asia): Their debut album from 1982 was one of my all time favorites. I've listened to it  several hundred times over multiple medias over the years. The vocals and drums seemed distant and small. The Mani-2 has brought them back to life.
2. Stan Meets Chet (1958 Sten Getz / Chet Baker). Listening to an album that's nearly 65 years old and sounds lively and full is amazing when you really think about it. 
3. The song "Sound of Silence" by Simon and Garfunkel. With the more forward vocals, it's much fuller and the harmony of the two vocalists is appreciated more than I had previously
4. "Casbah" on the Rich vs Roach album. The Mani-2 really makes this vintage song come to life. I think partially my Klipsch horns highlight the brass, but he Mani-2 brings them to life.  
5. Round Midnight (Miles Davis) - This is my current Nirvana...until I move the goal posts again.

At some point I'd like to upgrade to a MC cartridge just to hear "what's next" in my sound journey, but the urgency has gone away, as the phono-amp has pushed this back. In a small 12 x 12 office with not-so-optimal acoustics, the sound is terrific right where I have it. 

So thanks again everyone!