This is a controversial topic, I suppose. I thoroughly agree that taijiquan includes throws, joint locks, sweeps, and so forth. The question is how aggressively one trains these techniques, and whether there is a point of diminishing returns.
When I commenced my taijiquan training in the early seventies, I already had a few years of jujitsu and karate training under my belt. This had given me a pretty good foundation in terms of overall conditioning, stability in stances, etc., and naturally I had learned a great deal about how to fall, and the importance of that. My jujitsu dojo trained on tatami mats, and we allegedly learned how to fall in a manner to avoid injury.
During the first few weeks of taijiquan training, I asked my sifu if our taijiquan training would include learning how to fall. The response I got was somewhat facetious, but rather pointed as well. My sifu said, “In taijiquan, we are learning how NOT to fall down.” So, although we learned a great deal about the martial applications of taiji, there was not a lot of emphasis on falling or ground training. From one perspective, one could say that learning how to fall is fatalistic; if you spend a lot of time doing it, you may not be very successful in avoiding it!
Another taiji master I’ve trained with, Sam Tam, had a formidable early background in Eagle Claw (ying zhua), and this has evidently fed into his considerable insights into taijiquan’s qina techniques. He likes to demonstrate, for example, the incredible range of Rollback. It can be used to simply divert an attack, to send an opponent flying past you, into a summersault, or by a slight turn of the waist, Rollback can become “roll-forward,” sending the opponent bounding back (this involves an instance of “zhou,” or elbow jin), or it can be used in a form of joint lock that Sam amusingly calls, “making someone stand in a way that humans weren’t meant to stand.” I call it duck walking, in honor of Chuck Berry. Remarkably, this is in no sense a strong-arm technique, but is done with an extremely light touch. It is not painful to the opponent unless one tries to struggle free, so you are forced to remain in an awkward crouch -- a position, by the way that can be a virtual launching pad for a soaring leap through the air.
Elsewhere on the board we have discussed sparrow-hopping, whereby you learn to sense when your equilibrium has been compromised by a push hands partner, and in response you displace the force by hopping away with your frame intact. This is a nice alternative to falling down.
Instructors and practitioners differ in the emphasis they place on taking falls in training. I will just say that I know of many jujitsu practitioners who supposedly learned to fall without injury, but who eventually developed an array of knee, hip, and back problems from the repeated impacts over the years. You can be as macho about it as you want, but as you get older you may regret your misspent youth.