What about looking to something like old DRG jumps as a potential positional replacement on a single melee

Rather than an attack that has to be executed from a particular angle you have attacks that cause self negative debuffs or animation locks

So x attack can be executed from anywhere but it generates a rather long animation lock or an attack that after you used it it slowed your movement speed for 5 seconds after. Then you could introduce something like a SAM style rotation where if you are in a phase you physically cannot afford a movement penalty you could move around when you use that attack

So rather than organising where your positionals sit you organise when you can afford a “dangerous” attack and when you need to move it around for a different dangerous attack