mycroft, on 2014-September-08, 17:14, said:
...It's not that 2♥ negative is a *good* convention (it's not - for many reasons); it's that 2♣-2♦ immediate game force is worth the 2♥ (and 2NT, and potentially 2♠) fuddle.
Many thanks for the reasoning. I am not happy with an unlimited 2NT, because with a K (that's a positive for me) and a J, I would for example be bidding game, but then if stronger I would need different methods not thought about, and going higher than game may be risky. I suppose this is what you were implying. The idea works with the old double-positive. But then, I could keep opener NT range rebids with Kokish.
Perhaps what it boils down to is that a 2♦ negative gives better decision between part score and game, while 2♦ positive gives better decision between game and slam. I think I may be changing my stand, here. Time for a rethink!