25 really isn't that difficult to get if you choose to focus on Dodge.
Here's what I'm sitting at just now:
3% Greater Ocean Stance
6% FEAT: Flurry of Blows (Centered)
3% FEAT: Dodge
2% FEAT: Mobility (Crafted)
1% Item: Bracers of Wind ML (Cannith Crafted on Craftable +3 slot)
2% Item: Head of Good Fortune (Upgraded)
3% Item: Bracers of Wind ML 16
4% Item: Seal of House Dun'Robar
3% ED: Perfect Balance (GMOF)
3% ED: Walking With Waves (in Ocean Stance) (GMOF)
3% ED: Unearthly Reaction (Magister)
3% ED: In the Weeds (Shiradi)
3% ED: In the Weeds (standing still) (Shiradi)
Given that monks don't have an option to gain PRR from armour or shields, and given that you have to sacrifice other things if you do decide to focus on Dodge, then I can't see that it would affect game balance in any way.
In theory, I could respec and slot in Spring Attack and Combat Archery for an extra 4%, swap out non-monk classes to get Ultimate Ocean Stance for another 1% and get an additional 4% from Inspire Heroics with a bard in the party. So that would be up to 48% I make it?
So to me, the cap makes no sense at 25, it's too arbitrary a number.
Having to use Uncanny Dodge and Improved Uncanny Dodge to temporarily boost your maximum should not be the only way.
I would suggest either just doing away with the cap completely, or allow the following to increase your Maximum Dodge Bonus:
There could be a lot more Epic Destinies that should offer this increase too, but I'm looking at it from a monk perspective at the moment. Hopefully others can make suggestions for the other Destiny enhancements that would offer this.
+2 Ultimate Ocean Stance
+2 FEAT: Dodge
+2 FEAT: Mobility
+4 FEAT: Spring Attack
+2 FEAT: Combat Archery (Epic Feat)
+2 ED: Walking With Waves Tier 3 (GMOF)
+4 ED: Walking With Waves Tier 3 (In Ocean Stance) (GMOF)
+2 ED: Unearthly Reaction Tier 3 (GMOF)
+2 ED: In the Weeds Tier 3 (Shiradi)
+4 ED: Lithe Tier 3 (Shadowdancer)