I don't understand what you mean. I’ve never heard anyone from the production side of Terminator say that Arnie stipulated that he’d only return for the sequels, providing that they purposefully stifle the antagonist (besides, the T-1000 was plenty iconic). Even if that did happen with the Terminator sequels, what does that have to do with the antagonist of Blade Runner 2049? Surely you can't be suggesting that Harrison Ford (who's star power had faded significantly by the time of the movie, it should be noted) only agreed to return if the antagonist was made uninteresting?
I don't think it's particularly controversial to suggest that when you have a film that has its two biggest stars in "good guy" roles that somewhere along the line someone in production might suggest that they be given the lions share of the decent scenes and dialogue. That needn't have meant they deliberately wrote Luv to be uninteresting - just that Ford and Gosling had to be more interesting at all times.
Harrison Ford's star power may have faded, but they still wanted to get him back in a sequel to one of his most iconic roles so they're hardly going to say "take it or leave it". In his heyday Ford was known for having writers he'd bring in on at least some projects to make sure his character was written to suit his persona (and he was hardly alone there) - again, it's hardly controversial to think that a star like him, who would certainly have approval over the script, might want to make sure that he wasn't left playing third fiddle after Gosling and The Bad Guy.
I am not sure quotable lines is a particularly good judge of the quality of a film anyway. Lots of great films have no quotable lines and lots of shit has the odd good line that has fallen into the cultural vernacular
I agree (and really shouldn't have been banging on about this so much) - it just seemed odd to me that while Blade Runner is (in part) known for having memorable lines, BR 2049 seemed designed not to have any. But I guess it's to its credit that it doesn't have a bunch of shit lines delivered in such a way to make it obvious they were meant to become classics.