Well... if you spam it all in Shinten it should be somewhere from 3-4% based on your skillspeed. But that´s not even the point. It gives you the advantage to use all your kenki stuff way more. And playing positionals properly and using all of your tools, makes a huge difference and is defines definately the gap between a good and a bad / midcore player.
I don´t know how often i read "unmeaningful" and similar stuff yet. What is meaningful then? Give some examples? Give a real idea for a rework which doesn´t sound like action mmorpg?! I couldn´t even say, if you would be fine if those potencies on positionals would be doubled or needed for any combo, whatever. It sounds more like you want to get ride of them with the only argument "They have no meaning, so they´re annoying.", even if you´ve said in one sentence, you wouldn´t mind "more meaningful positionals".
In the next step it´s on top of complexity and you care for any damage loss, any uptime loss, several disengages, whatever... So how can they be unmeaningful, when you straight up lose damage, if you don´t play them?
I really don´t get it... either you´ve no real plan, you don´t know what you actually want or yes, you might be a prewriter with a 2nd account who tries to push this thread with another strategy.
From all what i read, i would clearly say in the end, melee isn´t for you. All what makes melees actual melees, fun to play and somehow challenging, seems to be a no-go for you and the contradiction in your posts is real. It doesn´t even matter if something has 10 potency or 100 in the end, when it´s fun to play and shows that obvious difference between "good or bad". It gives space to improve yourself.
But if you really want a class who can do whatever they want, at any time, without any damage loss, you should play phys. range. But beware, you could get bad RNG proccs or miss some in time due to doubleproccs / unlucky timings.
Don´t get me wrong, way more complexity and pressure on the player with different class-mechanics and way more important positionals would be a great thing where the player would finally NEEDS to improve, but i really don´t get what your point is in the end. It seems like everything but staying at the boss and playing 123 without any break is annoying for you and at this point i see no chance to make you somehow happy with melee classes without destroying the whole game and balance design. (It would be boring af too so...)