You've defined somewhat what IS is to you in terms of exercises, but, why do you need to do it? Why is it integral to aikido for you? Without the why, you can only blindly flail from what you are doing to why you are doing it. If you have a why as well, it helps you to work backwards and structure the what to make more sense - both ways. So... why?
don't know what Jason's answer but i can answer from my point of view. IS is the engine of aiki and since I am doing aikido, i.e. the way of aiki. personally, trying to fit IS into aikido is silly, since it's the foundation of aikido in the first place, i.e. there isn't a separation to put it back.
as for the question on hodgepodge, i thought martial arts by definition is a hodgepodge of things that helped us to win, and before someone threw a fit on the winning thing, try masakatsu agatsu (i hate losing to the phi dude). in the old days, the things that made you lose, you won't see it again. now a day, it's the opposite, because we can console ourselves that we are building our characters by losing. me, i hate losing in a food fight or wet t-shirt contest since i got a pretty sizable upper.