For me personally, I have a decent boxing 'game'. My problem is the opposite, actually, I struggle with good timing and distance while kicking when closing on skilled opponents who are determined to stay outside. Far too many of my kicks find 'air' rather than a solid target during my limited amount of competition fighting.

That's clearly a skill gap, as when I'm sparring less experienced opponents I can usually land kicks at will.

People who want to close to punching range are doing me a favour, as that's where I'm better. Not that I'm great, but my control of timing and distance is better in close.

I agree though, that that kind of pressure from someone closing the distance and throwing punches is a good 'stress test' of technique.

I look at it as there only being one range and thats either a person is in fighting range or physical contact or they not.So theres no seperation between ground,clinch, hand, feet range or whatever.Im not going to say to myself no kicking or no this or that im just going to do whatever oppurtunity comes up as thats what its about..random choas where I take whatever oppurtunity there is to fight/fight back drawing on fundamental body movements and fitness and an aggressive mindset.

Thai type kicking I feel is better as its about kicking at punching range and in combination with knees,clinch and elbows and punching.Plus the conditioning helps as bone on bone clashing is highly likely anyway,even if no deliberate kicking is done .Also Kick Thai style further out with the shoe and it can still damage.

How about kicking on the ground from the back? We train that. And also getting up rapidly kicking or stamping from a top position during ground and pound while being the one doing the ground and pounding.Nasty.

There has to be an adaption for MMA of course.A good drill is to kick and sprawl or try to sprawl half way half way though the kick or have takedown verses kicker.The takedown guy will win mostly but its a good dilema to try to figure out how to kick in that situation,not because I will purposly kick,just because it might happen as its so random anyway.I just dont know.Plus training against a kicker is important and so training partners need to be able to kick well so may as well get as good as possible,its full cirlce.
Just my view so far in my training.

I consider what I practice JKD. I try to place an arts delivery system in its right context. I have chosen to not incorporate traditional TKD kicks as I feel that my taekwondo background has taken care of that area. the only kick I have incorporated into practice is the savate scoop kick to the groin.

Ladies and Gents, if you don't have the scoop kick in your basic self defense arsenal, your really missing out. Doesn't take a long time to learn, nor to maintain as a useful tool. So even those more developed practitioners can use it.

No doubt that most people's kicks are weak. That doesn't mean kicks are bad.

When feeling an opponent by faints, jabs and hand hovering, throwing in a side kick to the stomach or a cross-stomp to the knees, especially off beat, can be a lethal technique, at least leading to more punches if opportunity presents itself.

I actually prefer leading with a side kick or a hooking kick, while in balance because they are the longest weapons I have. Punches come in after that, depending on the opponent's reaction because they are shorter range than kicks.