I would say that this is spot on. I agree 100%. So, you have to search, think, search some more, and think a lot more. But you will not get far unless you find something useful. So, searching is key. But that doesn`t mean searching, finding Judo, and sticking Judo in your Aikido because you think Judo waza to be more efective.
Or taiji for that matter.
You mean, like Tetsutaka Sugawara
The whole "pure" thing seems quite odd, considering that it was the Aikikai's assertion for many years that Aikido was anything but pure - that it was an amalgam created by Morihei Ueshiba. We now know that to be less than the complete truth, but when considering the question people should consider that their many (most?) of their teachers didn't quibble about purity.
Ueshiba was certainly open to experimentation, and sword that he brought in from Kashima Shinto-ryu is now a standard part of many Aikido people's training.
Most of the koshi-nage that folks do today was brought in by Shoji Nishio and Yoshio Kuroiwa - not Morihei Ueshiba.
I've seen Mitsugi Saotome bring in things from any number of sources - anywhere from Seitai Iai to Karate to his own imagination (not a bad thing, IMO, but it wasn't Morihei Ueshiba).
Morihei Ueshiba hated what Minoru Mochizuki, probably one of the least "pure" Aikido folks ever, was doing so much that --- he wanted to adopt him as his successor before the war and make him the head instructor at hombu after the war (Mochizuki declined both offers). Kisshomaru later endorsed Mochizuki's tenth dan promotion. Wait a minute - wasn't he one of those guys who stuck Judo in Aikido?