Good point about the drivers head size compared to tiny irons. I've recently gone to a bigger cavity backed iron after years with blades (Mizzy MP33 to MX200) and I'm just starting to dial the 200s in now. While they may not be quite as satisfying to hit as the 33s it's not half as bad when you don't quite get hold of it. For example, hit a slight toe with the 200s and it will still go maybe 90% as well as a middled shot, try that with the 33s and you're talking more like 50-60%.
Like you say there's hardly any tour players using blades anymore, so if they think it's fine to play with cavity backs then that's more than good enough for me!
MP33 oooooohhhh 1 of the sexiest irons ever made they will be remembered as a true classic