I will help you test that, my gorilla.
The reason the existing addons are subpar is because the server handles target selection and does not actually send it to the client in real time. When you combine this with the poor performance in instances, anything solely client side will be unstable. I don't write for windower to begin with, but a correct implementation of an improved autotarget must incorporate the server to be reliable.
they lack the frame perfect execution to beat JA0, so they're forced to leave it on.
Frame perfect execution isn't good enough, because it's actually a server driven race condition. If you hit switch target and it reaches the server after your target dies, the server can still send the packet indicating autotarget was processed and cause your client to switch to the autotargeted monster. This is only a problem when instance performance is dipping, so it's mostly an Asura issue, but still wanted to point out that it's not just skill-based.
How about we just remove the TP penalty and call it good? I feel like none of the other beef is filling
I don't think the tp penalty is the main/only concern. You have your delay reset, you lose damage, and you have to press additional buttons[seems most DPS players prefer to do this as little as possible].
My proposed system would allow addons (like AutoTargetAssist) to actually work correctly and keep your weapon delay and engage window up. Any solely client side system does not reliably accomplish that.