Doesn't that indicate to you that the stealth/detection system has problems -- at the very least as it applies to planets?
I personally sort of liked the idea of all planets becoming visible automatically upon entering a system. For one thing, it means that the ships will be able to move around the planets in combat like they're supposed to, and more immediately relevantly, there would be a definite point at which a planet is "explored". This means that the player can know with certainty that systems that he has been to do not have any planets that he doesn't know about, which means he doesn't have to keep re-exploring the galaxy every-frickin'-time he gets a new detection tech.
The thing I don't like about it is that it means that even very stealthy empires can't hide their planets as well, even from empires with poor detection, because all they have to do is go into the system to find all the planets. So here's a possible solution:
Upon entering a system, you automatically gain basic
visibility of all planets that you don't already have partial/full visibility of. This means you can't tell if/by whom they're owned or what the environment is, etc, or interact with it meaningfully (knowing the size might be necessary for space combat purposes). That may seem to make it super-obvious that there's a stealthy player there, but not if there are randomly stealthy planets strewn across the galaxy (relics of the precursors, perhaps associated with the Ancient Ruins special, or some variant thereof).
That way, the player knows for sure when he's seen all the planets in a system, and only needs to re-explore a handful of specific locations when he upgrades his detection. Stealthy players on the other hand, can still hide their planets without immediately being discovered by low-detection empires when they enter a system.