I honestly think the key to a good series is if the producers genuinely try to matchmake and not just put in “big personalities” who aren’t compatible with anyone else in there. For example, the reason why S5 was so good is because there were genuine feelings involved, Amy fell hard for Curtis and the fall out was epic. Amber fell for Michael and look how that turned out. None of the couples last year were believable. The real drama from LI comes from people having real connections and if they focused more on finding matches for people and not the best future influencers they’d have the show they want.
Edited to say, look at the early early series for examples. S2 was epic and have two couples that are still together now. I don’t think there’s any couples from the last two series that are still together.