I think that if uke resists and tori switches to another technique then tori is missing a chance for growth and learning by avoiding the problem.
I was probably unclear. What I regard as rather pointless resistance is when uke knows that tori should do a specific technique, and resists that particular technique forcefully, in a way that is contrary to how an attacker would or should behave.
For example, both ikkyo and shihonage involve bringing uke's arm up. Some uke resist it by pulling their arm down with great strength and commitment - even before the aikido technique reaches the moment when to lift uke's arm. In such a case, tori should not fight this force, but join it, which would lead to another technique - and that technique, agreeing with the direction of uke's force, is a piece of cake.
To me, that is quite meaningless. Also, by such behavior uke is actually weakening him- or herself, by committing to resist a certain technique and thereby becoming extremely vulnerable to other techniques.
Am I making sense?