HI Clint,
I understood your original question just fine.

I love the Classic airplanes. And I DEARLY loved my USA-1! (and my Vulcan, Ares, P-47, ......) It flew just fine in some fairly nasty air. When it comes down to "building", I, too, enjoy building a Classic model more. It's just a bit more exciting while I'm cutting, gluing and sanding. Maybe it's just a "nostalgia" thing.

Now, as you say, "ADVANCED" class as far as competing. Will a Classic ship do it there? Yes, and no. I do agree with Brett and PJ, there are some things the "Modern" plane will do that a Classic probably won't. I have flown a VERY good "Modern" plane, with a top line power set up and it is "different". But, can
I fly "good enough" for it to really make a difference when I go to a contest? Probably not. And, the top pilots can fly a Classic plane very well in all but the worst conditions (did someone mention Paul W. and his Cobra?). It's a conundrum, which I "think" is the proper term. (maybe not? LOL!!) But, IMHO, it might just come down to just how good someone can actually fly, and how many gallons of fuel they can burn. If the "stick time" is limited, then some of the finer aspects just don't come into play. Having confidence in a well trimmed model with a good power train, makes a difference, too, for those of us at "less than top levels". A lot of personal preference comes into play. It's really hard to compare what I am doing now to back when I was actually flying a lot, just to make a personal comparison. I don't feel things I felt then, and it's all a matter of laying off.
There IS a trend to "smaller" planes. Something less than the 700 sq. in. (or even more), now going back into the mid-low 600 sq in. category. Bob Hunt's Genesis Mk II (.46) was 700 sq in, then he went back to his 1980 Genesis ".40", a good bit smaller. Talking to him over recent times has revealed a trend to a plane around maybe 650 sq, in. as being what he was looking at. Dave's Thundergazer is less than 650 sq. in., right? I'm not sure about Brett's current plane, but I am guessing 650-670??
Pat J. is right about the Shark's. Either size is good to go! A LOT depends on engines these days (or "motor" if you're into the "watts" game

) and just a change from a "vintage" engine to a "modern set up" makes a great difference.
I guess what I am saying is that as we move up the ladder, we can use planes that are not the very latest models, but to be competitive at the top levels then there are certain things that need to be in place. At the local level though, a super zoot model/engine probably isn't necessary for several reasons, although it won't be a hindrance either, usually.... Anyway, we have to do what makes us enjoy the hobby!
Bill