I think to a large extent the gap in the higher weight classes is dictated by the number of fighters available to fight in it though.
I mean, look at the current state of LHW and HW in the UFC. They've barely got enough warm bodies to fill a top 15, and even then they've gotta trot out the zombie corpse of Little Nog. They let Bigfoot Silva go on a losing streak that wouldn't be tolerated at a lower, more populated weight class just because LOL it's heavyweight.
If it got broken down any further, I think you either wouldn't have enough guys to make a division (the same problem they're having with women's 145) or you'd just get existing 205 and 265 fighters doubling up.
That's because especially in the post-USADA era, the 265 pound heavyweight limit is kind of academic anyway. Most of the top competitive guys (Miocic, Dos Santos, Cain, Werdum) fight at about 240 and they're pretty clearly not cutting weight to get there. Even a 6'4 physical freak like Francis Ngannou comes in around 250. The only ones left weighing up around 265 any more are guys like Mark Hunt and Derrick Lewis (and all 7 foot of Stefan Struve I guess)
Anywho, point being if you made a new division around 220 or 230 I suspect it'd look kind of similar to the current heavyweight division - I'd be surprised if all those top guys mentioned earlier wouldn't be able to cut down to that, so it'd probably just be them fighting each other and a few 205ers who didn't want to cut quite as much weight.
I don't think the dearth of talent at the higher weight classes is going to change any time soon either - at least not until there's a LOT more money in MMA - because talented athletes that size can currently make a way more playing a range of other sports, without getting hit repeatedly in the head. The lighter divisions get more talent because they're guys who are too small to make it playing football or basketball or whatever.