As for Jump used specifically to obtain a Backstab bonus (as opposed to jumping to Disengage), I'm tempted to be cheeky and say "if you don't like it, don't use it". Just walk around the enemy. It may require a bit of practice, to make sure you don't trigger an Opportunity Attack (break out the move in several smaller moves). It also saves you a Bonus Action, which can be pretty useful if you're dual-wielding.
At least jumping has some sort of internal logic and a limited immersion, but will always feel like an unfair exploit as enemies don't really flank the player. Your suggested "cure" is even worse. Enemies always allowing themselves to be flanked in "slow-mo" will always jarringly remind any gamer with any discernible critical sense that turned based combat is a super unrealistic approximation of combat. Immersion breakingly so.
By making a powerful advantage (literally) so easily obtainable, Larian is diminishing, primitivizing, their own tactical gameplay. When something is guaranteed, people tend to get entitled and annoyed you have to repeat the time-wasting formality of this little ritual. For the people who don't like the legalized exploits made core-mechanic, you can of course chose not to use it, but you are always reminded that you are not only wasting time, you are actively engaging in self-nerfing which is counter to the very essence of computer RPGs. It's UTTER TRASH GAME DESIGN that Larian flatter themselves over thinking they're promoting "player agency". Same goes for all the other Larian cheese like dipping weapons.