Since the proposal would change stacking for Hide, Move Silently, Spot, and Listen together (and all other skills too), rather than in a vacuum, I fail to see the issue.
If you get to e.g. 100 Hide today with bonuses from every item slot, and 80 Spot also with bonuses from every item slot, then this change would (assuming all items grant +3, and wearing 11 items, now only getting bonuses from 1 item) reduce the maximum Hide to 70, while also reducing the maximum Spot to 50. End result being that you are in the same situation as now, but can make more interesting item choices than "maximum Hide".
I completely disagree it's not the same. It takes a lot of dedication to get too 100 hide or 80 spot. Those who can get there are making sacrifices to be a cut above the rest in that specific facet of the game. I'll steal "JustAnotherGuys" phrase of "dedicated spotter" in the sense that this becomes a game of cat and mouse (dedicated spotters vs dedicated stealther's) and it's absolutely lovely to be apart of

. By capping equipment, your going to end up with this sort of situation (example below) and ruin the cat and mouse game:
Spotter (non dedicated)
"My class gets spot, ill dump 33 points into it because I have the class skill, or its a background trait I added through the pop-up and its... only 33 points to block all sneaks from hiding from me basically across the board. add my one +3 spot gear, and with the +d20 spot dice roll, I now have the potential to see all sneaks with 56 or less. I don't need to do any more here cause I'm basically the max now to see them as its very unlikely they can get any higher, no other sacrifices needed... So I'll wear all my +4 AC gear or other +3 gear instead knowing I can see them."
Sneaker (Dedicated)
33 points in Hide and Move-silent (we need two skills to stay hidden), get +3 for each ... sacrifice feats so I can get the 'skill focus x2' to add a measly +3 more points, stealthy +2 points, and I end up with a total of 41.... which means I'm basically going to get spotted every time with no ability to get it higher). I guess if I want to take it higher, I am forced to play bard so I can use heroism... skill song... and other potentially 'non-fitting' rp classes just so I can sneak reliably again since those 'beat the cap'. A regular 'Rogue' who doesn't want to play magic and bards is basically dead at this point in the stealth game."
Like someone mentioned, a sneak really needs to be 20/21 points higher than a spotter to make it even viable. That spot check dice roll is just running over an over trying to find 'sneakers'. As you can imagine a sneaker getting caught is game over (which is usually dire consequences)

we stake our whole RP and being on this fact.
People who really want to be part of the 'mouse/sneak' play style are generally willing to 'go all in' to make it happen to avoid the 'cats/spotters'.... but adding a skill cap makes it so we have 'cats(dedicated-spotters)' but now also 'kittens(added 33 points of spot on any class) who have way less dedicated/investment 'join the hunt' while only having to 'dabble' in their skills... Since all the mice can't sneak that good anyway and are fighting that +20d dice roll every 6 seconds....
Ugh sorry this is really becoming "Sneak vs spot" now.... If you want to put skills caps on all the other skills *shrugs* just please leave Hide/Move-Silent + Spot/listen alone so the 'cat/mouse' game isn't killed

If the answer is -no- and this change must affect 'all skills' then this topic really feels like an attack on us "dedicated" RP sneak players.
