I used your method (3), linear interconnections between many points before live and I still do it that way mostly. The problem, I'm pretty sure that curves are marked as implemented for ableton and we will not see any enhancements for a couple of years in that department. From my point of view they wasted time. The current implementation doesn't solve the problems with curve. I don't see a benefit.
But you're right, we'd both be happy to see more flexible curves. Have a good day!
