You’re right, that for a given amount of skill, it is easier to do X with a bike that is easier to ride. It’s a no brainer, really. The thing is, almost every bike — other than the ones we all recommend to beginners like the broken records that we are — is not the easiest bike to ride. It doesn’t matter whether it’s a Goldwing or an R1; it’s not going to be easy to get it to balance at 2mph if you’ve never tried. You have to practice. But once you do, it’s second nature, just as it would be with said beginner bike.
I probably sound dismissive when I say this stuff, but you’ve missed about 60% of my posts on this forum (at least based on when you became really active). You’ve missed my talking about how many hours and hours of failure it took before I could keep my GSX-R inside the box on the MSF figure-8 drill. This stuff is not easy, especially on a sportsbike, and I don’t mean to make it sound like it is. I still feel uneasy if I haven’t done it in a while. I just don’t think that sportsbikes are really any harder to ride than big Harleys, powerful tourers, etc. Sure, it’s a different set of skills and challenges in play, and some riders have a harder time dealing with sportsbike-specific issues than others, but the other bike types have their challenges as well.