My comment applied to a whole raft of plugins really, not just T-splines. Rhinoworks, VSR Shape, T-Splines, Scan and Solve, etc etc. I won’t be in a hurry to move to V6 if it means that I lose that lot.
It does seem a flaw in the Mcneel armour. Say, tomorrow, another developer turns up on the Rhino scene and announces another silver-bullet plugin. The good folks here all get on board, help out with growing it and making it useful (as G’s comments). What’s to stop those developers doing exactly the same thing as those that came before? Rhino is the long term loser, as all we do is strengthen the opposition.