Mike, I think your problem is in the assumed answer to this question (snipped):
But I do hear, "Sensei, what happens if uke doesn't follow the technique? What happens if they resist?....
And then a response usually comes along which typically goes something like this, "Well. Honestly the only really safe way to accept these movements is to follow along with them, if things are done rapidly and with conviction uke is going to get badly hurt by trying to struggle".
Which is where the problem comes in....it is utterly and absolutely unrealistic to expect that anyone not specifically trained in Aikido (or possibly something damn similar) is ever going to give you the proper ukemi to avoid be dramatically hurt by a well executed Aikido technique.
An aikido technique isn't like a sausage machine, where you stick an attacker in one end, select a speed and then flick the switch. Its very possible to apply any aikido technique without (seriously) hurting the attacker.
Its like you've got it the wrong way around: A shihonage that requires a big breakfall isn't a technique designed to flip someone in the air - its a technique designed to destroy someone's elbow/shoulder and land them on their head. If you're doing that technique, then that is the outcome you're aiming for
. In practice we learn ukemi to survive it just so we don't run out of ukes too fast. You don't want to break your attacker? Don't use a variation that'll break them - use a different, softer, equally-as-effective one.
One of the beautiful things about aikido is that it gives you that choice - to inflict damage or not, depending on the situation. I've had several students who work in special schools or hospitals where damaging your attacker just isn't an option. Having that range of options (and practicing though the whole range, not just hard or just soft) is one of the most important gifts aikido has to offer.