My Naxx run last night seems to show that the expertise cap for dodge is higher than 25 / 6.25%.
I have Vot3W talent for 6 expertise points and 157 rating for the remaining 19 points needed to reach 25 expertise, however I had 2 melee swings and an Obliterate dodged during our run.
I had the exact spec and gear on that the armory is showing currently. For glyphs, I currently have:
Major: Blood Strike, Icy Touch, and Obliterate
Minor: Raise Dead, Pestilence, and Horn of Winter
I'm new to using WWS so perhaps there is something I'm not aware of could be causing the dodges so I'll post it here for the experts to review.
http://wowwebstats.com/4x5b2owmg2d35
The dodges were at:
02:52'51.068 Darkcaid Obliterate was dodged by Maexxna.
05:11'50.335 Darkcaid attack was dodged by Grobbulus.
06:43'46.247 Darkcaid attack was dodged by Kel’Thuzad #3.