Or maybe carrying less weight on your feet, which gives them less work to do. It's possible that something a bit less chunky than your Power matics will make life rather less tiring, with a pair of good off-road shoes coming in at around half the weight (or less, if you fo for something like Inov8 Roclites).
There is the temptation to look at your past sprains and tell yourself you need more ankle support and big chunky boots, but arguably the best ankle support for most people comes from letting your body do it as it's evolved to do (and I'm speaking as someone who's had 3 ankle sprains worthy of crutches in the past). Sprains tend to stiffen ankles in the long term more than weaken them IME, and my past sparains have never been an issue in lighter footwear. In other words, I think prop them up if they've just been damaged, rather than as "preventative maintenance" which actually prevents them moving naturally and building up normally.
Optional insoles are targeted at doing particular jobs, so the first thing to do is decide what's not quite right about your new footwear and how it might be fixed (if they're fine then just go with what's supplied).
There are a few things insoles may do. Superfeet are meant to fettle your gait slightly, Sorbothane ones are meant to add shock absorbtion. There are also volume adjusters which alter the fit inside a bit to reduce rubbing. These may all be useful things, or they may be a way of wasting money to little end.
I use (and like) Superfeet as I tend to over-pronate quite badly, and I find they help against that, but if you've got a fairly neutral gait I can't see particularly much point, especially given the price tag. I'm not convinced they're going to do much in a relatively chunky boot as the boot will have quite an influence on what your foot can do: while I use Superfeet in light shoes I've never bothered in big boots because my pronation issues don't seem to be a problem in them.
So, before you go out and buy something to change your boots, what's wrong with them that you want to change? If they ain't broke I wouldn't fix them...
But if you use and unlined shoe and then a waterproof sock, like many advocate, isn't that the same thing as a line shoe?
Downsides of a waterproof sock is you lose a lot of warmth. If you saturate the outer of a waterproof sock then the liquid will be much closer to your foot and conduct more heat away. A waterproof shoe allowing a layer of air in the outer part of the sock should be warmer.
The upside of a waterpoof sock is it's easier and more practical to change in and out of them according to need on a walk, and cheaper than having two pairs of shoes and selecting before the walk. They're easier and chepaer to replace if they start leaking.
There are times when a lined shoe/boot really is a better option. But there are also times (more of them IME) when it's a worse one, and the market forcing me to choose one I don't want miffs me somewhat.
Back to my previous plea for a new version of the Scarpa Helium, it's a compronmise between the approaches of waterproof or teabag, and like a Soft Shell there are plenty of days where a compromise actually works best. A bit of water resistance and more breathability. Salomon did do a "soft shell shoe" a few years back, haven't heard much about them lately.
I share your pain. Specifically, I would very much like a new pair of Scarpa Heliums as mine now have a flat sole and the lining is coming to bits at the back after many year's wear, but there's nothing quite like them in Scarpa's range any more.
I'd picked up a pair of a later (non-membrane) model (Axis?), but there's quite a bit more mesh which while being okay on a warm day is a downer on a damp one. I don't want a miracle Super-Duper-tex liner that completely fails to drain, but I do like something that resists external moisture a bit more tenaciously than a teabag. The Heliums have a lot of suede all around the lower part of the upper and that does a very good job of keeping damp out, and they dry pretty smartly when the insides do get wet and they drain without having to take them off if they get properly wet.
In fact you have prompted me to send off a rant to Scarpa right now!