I agree on the idea that the gameplay's gotten stale from player's being way too overpowered and while I'm not against OCP gear on face value, calling them not OP feels misleading when some of the items give +40 all stats as a side-benefit.
Considering bio5 cards which give +20 all stats are considered BiS for almost all crit classes, gear with +40 all stats is obscenely powerful.
Some items would be interesting to see such as the injured eyepatch which boosts auto-attack berserk builds, but what if there's an auto-attack rework on KRO that suddenly makes auto-attack builds really good?
You wouldn't be able to get rid of the injured eye patches in the economy afterwards and that's the real danger of introducing OCP gear; you need to be willing to full send changes like that in-case the source server introduces reworks which alter the plan you laid out by introducing new items in the first place.
Honestly I think RO would benefit from some custom changes given the state of the game currently but it feels like the game is slowly healing to some extent, I look forward to how things change in the future and I have faith in how things are going.
Part of the problem is definitely the exp rate, being at level 250 results in absurdly lower damage output than being at level 275 and it would affect farming, economy and partying severely if exp rates were slower but I personally can't think of what you'd do at this point into the server given the fact everyone's already max level or near it.