I agree with you vis a vis the conditioning routine - you need to spend some dedicated time just conditioning those strengths . . how to condition "what" seems to be what's partly in debate here on aikiweb, between different styles, cultures, yadda yadda - since there's been so much secrecy between methods and approaches.
On top of that, I don't think you'd disagree that the next challenge becomes about how to apply those different strengths back into a martial arts practice, whether it's a sporting martial art (MMA, which I'm probably most curious about and hope to be getting back to soon after next kid and more time working basics), traditional martial art, etc. I understand what you're saying that there's fundamental strengths that serve any milieu or outlet, but I think there's a "break-in" period as well - especially if you're walking in cold somewhere new.
Of course, the converse of that is that if you haven't spent the requisite time getting at least the basic skills of IS then it is a moot point and you're just going to be doing the activity at the school/gym (which may be great or not-so-great). I'll be curious to see how things work out in the next few months as I've been trying to let go of a lot of things while building up new stuff from the inside out. I expect some conflict and then when I first get hit or competitive will be curious to see if I slip back into old habits, go for the win, or keep my head and try to stick to my game plan.
I like Diane's article, too. I liked training weapons with her even better!
As far as MMA goes you have heard me say it here many times and in person. "MMA is the great equalizer." and that includes freestyle weapons. Anyone can get tagged in a fight, and you can win, then lose against the same guy in the same day "S_______ happens!"
I see IP/aiki and fighting as two sides of the same coin. I don't want to do either- without the other, but others certainly can and do it well.
What to train and how to train it and how to use it is an interesting discussion in a lot of places. Ask around and read and we find that the real experts do not all agree on just what is not necessarily useful in fighting.
What if very powerful demo movements are crap in grappling?
What if some of their prized moves are actually like amatuer hour against a good grappler who will read them like a book?
So other than partaking in more noise on the internet I see it as a personal choice and testing. I see it as a conditioning and use question, and they are not all the same.