Cady, well, it is an interesting riddle. As I noted, some may choose to quit aikido or never start aikido. Some may view training in IS and aiki as an inherently superior activity and anything else must be subsumed to it.
But what I pose is the question what if aikido is, to someone, far more: anything from a wonderful exercise to embodied crisis intervention on a physical metaphoric level to a spiritual practice to . . . and they wish to integrate their aiki/IS training within whatever methodology their aikido offers (or their teacher offers) - without doing violence to the dojo/style they are training, while enhancing their own skills. That poses a number of dilemma, one of which you note.
Another question arises in pure IS/aiki training apart from a specific martial art (which carries culture, tradition, an ethos, etc.). Some would claim - and it's right for them - that they have no interest in any of that, or even, that it gets in the way. But what if a certain martial art is essential to someone, and they are willing, even, to take a longer, even incomplete road towards IS because of their loyalty to their martial arts practice, if that is, in fact, unavoidable.
I'm aware of koryu that have some level of IS training (often rather attenuated in this era). But should they practitioners abandon every aspect of the ryu that is not IS training? The question becomes more pointed if it can be correctly asserted that their particular methodology is a limited subset of the possibilities of IS training, that in some respects, their ryu gets in the way of 100% comprehensive IS skills. The counter to that may be that they have integrated specifically and only the technology from IS to accomplish what the ryu is geared to accomplish.
So, back to what I believe is your initial point - it is certainly conceivable to me that some aspects of aikido training, as it is structured - - - - as it's always been structured - may get in the way of IS/aiki training. Maybe not, maybe so. It'll be interesting to see what people come up with.
Oh, and by the way. Some years ago, on more or less, an intuitive basis, I started structuring aikido along what I referred to as five themes (kyoku), using five vectors from ikkyo to gokyo. There is a phenomenal series entitled KAJO
, that takes this far further and with more rigor. The writer, proves, I believe, what I've long asserted - that Osensei consciously selected specific techniques from the larger corpus of Daito-ryu for specific training purposes. This essay takes into account Roppo (six directions) - and, in my view, establishes that the particular techniques (including kokyunage/iriminage from the 1930's - a reference to a discussion on Kobayashi sensei's reminiscences
) were structures as a comprehensive "container" for IS training, as Ueshiba viewed it.