hmmm I always remember wherever important stuff in the galaxy is, even on 120 planet games. My use of the 'P' option is good enough to instantly see where what is. P8 is always ARS for example, without exception.
And i consider the dyson sphere to be important enough to always remember where it is. Besides, all the enemy worlds around it are (still) always on alert, meaning you should notice the difference in amount of ships on it's surrounding planets.
But there are some things I dont have a P for, like raid engines. Or multiple targets on a single planet and I can only mark it with one P at a time.
I suggest that we get more options to mark priority targets (P0-P20? P30 perhaps even?) and that we can somehow select multiple numbers for a single planet. If there is a dyson sphere, ARS and a cursed golem on a planet for example, I want to be able to mark it as P9, P8, P6. Instead of always having to pick one number and then forget there's a whole bunch of other stuff on that planet too.