So far, I'm hearing that other arts address the issues of compassion, unity, mercy, etc. Which is what I said, adding that Ueshiba actually tried to act on those high principles, with the implication being that this attitude imbued his art. Or at least tended to; this is a martial art, and I don't expect absolutes of sweetness. Likewise I wholly agree that, at anything like full force, Aikido does not take it easy on uke. But if we are talking differentiation here, then I think the answer has to do with how the founder's intention was manifested, to whatever degree. By contrast, Takeda studied esoteric Buddhism, but he also drew a knife on his son. These were two very different people, and their arts reflect that fact.
As for the number of techniques, I'm hoping someone will be dropping in to confirm or deny, but what I understand is that, while most Aikido correlate to Daito Ryu, the opposite is not true.
Finally, I am painting in broad strokes here; considering how close the roots are, and how much the styles of both vary, I don't expect to find much in the way of absolute distinction.
There's no question that Takeda was rough on his son - on the other hand, I'm not sure that it's possible to judge a person of that period by the standards of this period, or even of Ueshiba's period and background. Still, can Takeda's parental style reeally be an argument for differentiation? Quite a few Aikido folks have horrible skeletons in their closets, yet are still respected teachers of the "Art of Peace".
Here's an interesting quote from...Sokaku Takeda:
"The purpose of this art is not to be killed, not to be struck, not to be kicked, and we will not strike, will not kick, and will not kill. It is completely for self-defense. We can handle opponents expediently, utilizing their own power, through their own aggression. So even women and children can use it. However, it is taught only to respectable people. It's misuse would be frightening..."
So far on this thread I haven't seen much (any) evidence presented for a significant variation in core technical principles. Some people have brought up some points of variation, but I have to point out that Daito-ryu varies widely within itself, and the same is true for Aikido.
Then we have the spiritual angle. But then, there are many people who teach Aikido with a very limited spiritual overlay, just a general moral ethic, and they are considered, without argument, to be respected teachers of conventional Aikido.
So where do that leave us?