Five difficulty dice max kind of don't apply on opposed checks (I think).

so your base of 5y1g becomes 8y with frenzied attack, upgrade that six times for 11y1b melee attack. Get an upgrade from a friends triumph, and use a destiny point, that is a 12y1b dice pool...Hope ya got 6 dice sets laying around for that

And thinking about two characters on that level making opposed check. Total number of dice rolled would be 12y1blue12r1black, + possible setback/boost dice. (And, yes, I know this is highly hypothetical situation.) Coming from Shadowrun / Exalted background, I don't like large number of dice, but it also doesn't disturb me.

Disclaimer: I'm total EotE noob, so there may be something I have understood incorrectly, or missed.