I'm 46 and I started realizing my swing wasn't as good as when I was in my 20s. I played the AP2s for several years, and they just were not forgiving enough for my game.
So this year I got some new irons. I chose the Callaway Apex. They feel great, forged head and are very forgiving. I tend to hit on the toe a lot.and barely see any distance loss from toe hits.
I recommend trying them out, the feel will be very close to your Mizuno's.