I'm finding that even with WT, I approach it differently as I get older. You know, not so many reps. of chain punches on a really hard wall bag, less full on sparring and a lot more chi-sau. I've got a few joint issues too. You learn to adapt. And, I've met some 'chunners a good deal older than any of us, and they are still lovin' it!
I would have to say that I'm not going full out like I was 10 years ago but what I like is although my training isn't as intense as often, I don't have to modify my technique. In fact, I find my skill improving.
My si-fu tells us to train as if we're old men. In other words, not to muscle the techniques. That way as we age our skill can continue to improve, and we have a lifetime to develop it. If we wait until we're "geezers" to soften up, then we've only given ourselves a few years to develop soft skills.