Dungeonfrog: Are we talking about concealment gained from spells such as invisibility?
Abilities that grant miss chances and concealment are quite common such as blur and darkness.
Depending on the source you have quite a number of options to deal with it, such as the light spell, any item that grants true seeing (or in case of darkness darkvision is enough), true vision spell, any ability or feat or spell that grants blindsight, etc, etc.
Note that both concealment and ways to break it are interwoven in multiple classes so a PC party can also make use of it.
Examples are: Zen Archer has an ability to ignore total concealment, Oracle curse and the instinctual warrior archetype. Ihave to look, but I think a witch also gainsa Hex that gives blindsight.
If you fail to spot a creature with Stealth it would mean the hiding creature has concealment when you try to interact with it.
So removing concealment would mean breaking down multiple spells, feats, classes and the entire stealth mechanic. Not really an option.
Do too many creatures make use of it? Demons and other outsiders have a lot of spell like abilities and spells such as invisibility are pretty common. Spells that grant miss change as also pretty common even before mid-level.
It can be annoying, but so are an abaundance of creatures with regeneration.
I do not think concealment itself is a system that has to go, but if it is used too mutch it might become bothersome, but that is down to encounter design. Ultimatly, it comes down to personal preference if you find the number of encounters where concealment plays a large role too high.
Perhaps a poll would show if encounters need to be rebalanced. By rebalancing I do not mean made easier, but rather more varied.
no talking about concealment that some boss's have as extra bonus to make them almost impossible to hit with weapons/bows you need to roll 20/20 to land a hit.
