Best I can say is probably to not overlook the *wrestling* side of it. The better you get the feel of the professional wrestling aspect, the tighter the game should feel as a product. That means a few things. Just going by the few shots I see on your blog, a few obvious bits stand out. The characters appear to be dressed identically, only differentiated by hairstyle and colour-scheme. Early days and all that sure. But one of the cornerstones of wrestling is *character*. That means being able to, as a wrestler, get your distinct personality and identity across in the ring, from how you move to what you look like, and it's got to be clear enough that the people in the cheap seats can get it, all the way at the back of the bingo-hall / arena / etc. Which is to say, I'd like to see characters who stand out as very different, with distinct ring gear and looks where possible. You've only got so much to work with, so they're going to have to get personality across with what details and design elements you can afford to vary without creating problems for yourself.
A follow on from that is the structure of a wrestling show. Namely, the Heel / Face dynamic. Those personalities should vary in terms of whether they are good guys or bad guys too. If there's room to give distinct moves to the characters, I'd look for ways to give the good guys flashier moves and the bad guys more dishonest ones. It helps give structure to what's going on in the ring, if nothing else. As for the actual wrestling manouvers? You've got a still of a pretty decent boston crab in there, but the punch looks way out. That's not a real effort to hit someone in the face, that's the stance from some kind of Karate kata. My advice on this point is that you should watch plenty of wrestling, get some good references for your animation. Look at how a few different wrestlers throw punches, and get a decent reference in particular for any hold or move you include. The Full Nelson submission on your more recent update also looks a little backwards. You've got it as a lifting move there, her feet off the ground. It's usually more about forcing the head *down* than the shoulders up, so to speak. The idea being that it's putting pressure on things like your ability to breath and blood flow and so on, so you either tap out from the pain or pass out from getting sleepy. Little things like that can make all the difference.
What else springs to mind? Oh, of course. The show itself. Which is to say, the central gimmick of the game. Your game revolves around a pornographic wrestling show. It's about wrestling matches that involve deliberate h-content, as part of the rules if I understand it correctly? Well, consider what those rules, in the fiction of your game, would imply. What story do those rules tell.
If it's a matter of the first to cum loses, what does that wrestling show look like? You have a wrestling match where the two wrestlers try to do that to each other, and eventually the audience gets a single climax that signifies the end of the match. What kind of competitor would be particularly suited to this combat? See, the person who cums *loses*. So it would make sense that your likely champion and the more fearsome opponents would be those competitors who are *more frigid*. Implacable women with control over their libido who can take what their foe is dishing out and not lose their composure. If you change the win condition,(Say, to a regular pinfall or submission for example) you could instead have a situation where cumming is likely and potentially even a significant disadvantage, but you don't have a match that ends the moment someone gets off and I would imagine you're leaving more conceptual room for sluttier wrestlers to be better at that kind of environment. Both are valid directions to take the game, but it's going to feel very different depending on which one you take.
Oh, and I do think that a championship or a trophy if it's a tournament setup is basically required, likewise you should have characters who are more of a threat and wrestlers who are there to get beaten convincingly and easily. It keeps the wrestling feel but also gives you potential for managing the difficulty curve and all that jazz.
I think it's worth keeping an eye on the themes for the non-wrestling side of the content as well. Is this a game about light, wrestling themed ryona? Is it more about humiliation and physical domination? Are the characters there because it pays well, or are they passionate for the sport? Either work, and might even vary from character to character. But this is a fantasy, so they might even be compelled to compete because they're prisoners / slaves trying to earn their freedom or any number of other things. Whatever your focus is, you should make sure the gameplay goes well with that.
I mean, if it's about the whole angle of two wrestlers competing for physical dominance, humiliating each other in the ring by using the sexy moves as part of the combat, it'd be worth checking out something like "Ultimate Surrender". Their gimmick is that it's unscripted girl on girl wrestling porn involving legitimate competition. The fight to strip each other, perform humiliating sexy moves on each other (having established control) and the winner is determined on points and then gets to do whatever they want with the loser. It's a pretty good structure and a very similar idea to the game you're putting together in some senses. I feel it works particularly well as a gimmick because they take the rules and competition seriously and because the rules are designed to get across the themes they're trying to get over.