Trollson's post represents the angle we're taking, and what we're trying to achieve.
I would feel that i'd failed in designing an attribute system if it needed a cap.
Echoing what trollson said; there will be attributes that will be inherently good for particular types of melee fighters, or particular types of mages, etc.
That said, it was planned to have skill level requirements for the usage of equipment/items relative to those skills,
but it was always going to something where the effect would only be felt in the early stages of the game. Players will be at the required skill level where they can use all equipment available for their nexus class quite quickly, in just a fraction of the time that will be their 'game life'.
EDIT: In regards to an a/d (or any skill) cap, there's also no plans for this
in QELServ (although you may get a little 'for fun' (and development info gathering) game in the meanwhile that will have such a cap
). The exp requirement for next level once people are nearing our desired 'softcap' in QELServ will be huge.