Punching is a funny thing. There are arguments that the human hand is ill-suited for striking, but there are equally compelling counterpoints that it is almost damn perfect for the duty. I think it is both if you're willing make a couple of adjustments.
When I was a police officer, I worked as a trainer and a quarry in our agency's training section. It was a good experience, but the limitations of the time and training opportunities made it such that you had to get a lot of information out in as short a period of time as was budgeted. It was a little silly in some ways, given the stakes involved in a situation in which an officer might need to rely on combative skills should probably maybe kinda get more attention, but hey--who am I? Nobody, that's who.
ANYWAY, because of those limits, I didn't have the same luxury to explore techniques or concepts with any real depth--at least not the depth that would be afforded my kickboxing or boxing classes--and it came down to two things for me. The first, build off of existing strengths when possible; and second, give everyone something immediately usable.
That latter point? I suppose that's the whole idea of keeping it simple, but simple doesn't help someone if you don't tell them what simple is. I can give you an axe and you might use it as a hammer or a paperweight or who knows what else. But if I hand you an axe and say, "Hold this handle and swing the edge at anything you want to have a bad day, whether it's wood or a skull," well, that is immediately usable.
In much the same way, I created a training video that went on about hand safety and broken bones and straight lines being advantageous and all that, but do you know what everyone who has seen that video remembers? Here, you watch and see if you can figure it out.
There were actually two key pieces of immediately usable advice, or "advices" as Arnold Schwarzenegger would say. (Go watch Pumping Iron if you have no idea what I am talking about. Also, shame on you if you haven't.) The first comes at 1:14 and is as simple "hard against soft, soft against hard" and you know what? Everyone remembered that.
Not only has it kept my hands mostly healthy for as long as I have been throwing mitts, but officers I didn't even know came up to me much later and told me how it stayed with them for years after they heard it. I really can't distill it down anymore than that, so I'm glad it worked. It still does if you can remember it, too. Know when to punch, know when to slap, and let the target decide which. Hard against soft, soft against hard.
The second happens at 1:50 and it is a disclaimer of sorts on my part. Don't punch if you don't practice. Seriously, you will just hurt yourself--and people did. The agency I worked for lost hundreds of thousands of dollars over the years to officers with broken hands from on-duty incidents, not to mention the surgeries and rehab that the officers themselves had to deal with away from work. Nobody needs pins and plates to hold their fist together, so why even risk it. Find another way appropriate to your abilities and tools; there is no loss of honor in doing that.
But I have to assume that you train at least a little bit if you're on this site reading these essays, so my advice(s) is to mix it up in your shadow boxing, your drills, your training, and everything else combatives related. Play around with striking surfaces, both what you're hitting and how you're hitting.
In traditional martial arts, hand variations are numerous and everyone thinks they're useless now that MMA has taken over. The truth is, those variations exist for a reason; traditional martial arts was all about anatomy. The originators tried to make hitting something greater than the sum of its parts. Hard parts and soft parts, as it turns out.
Stay true to those principles and keep your hands healthy for years to come.