Both require intense focus but a stepping back from control (or intent). Perhaps what this means is that the process is more important than the result. Or that the process is the whole of the thing, and the end result is never to be attained.
Yes, maybe that's it. Is there ever a perfect form, in Tai Chi practice or in painting?
I would say certainly not in painting.
Because as you practice, you grow and live and change, and the desired end must change with you and with your expertise as it grows with practice. It never ends.
With Tai Chi, the practice is the goal and there is never a perfect final form because there is never an end to the practice - not as long as there is life.
Gosh, I don't know...