on the Stat Page > All Stats, Elemental Critical has a cap of 40, while on Stat Page > Offense Elemental Criicals are shown to go over 40. my personal thought is that the 40 cap is for the Wizard Talent Wizardry, but I haven’t ever tested it. most Players are satisfied with Elemental Crit +30 for most builds, while there are only a few builds that need Elemental crit of +40 or +15.
change Empower on Pet to Deadly Strike, and then change the Fester Nature to Empower. what you lose from Fester you more than make up with going from Empower 10 to 20 (from +25 to +50% more Power Stat), and Deadly Strike +40% is way better than +30%, especially when you have Brutal Mythic on your Build.
what makes Empower so awesome is that Power Stat is in the early part of the Weapon DMG formula. Wizards can have Power over the max of 103.
Power 100 x 1.25 = Power 125
Power 100 x 1.5 = Power 150
each point of Power is 75 DMG.
(((Base Weapon DMG + Power) x (Item Quality x WD%) + WD+) x ED%) + ED+
(((8320 + 11,250) x (1.25 x 3)) x 6 = 440,325
440,325 x 1.5 x 3 x 3 = 5,944,387.5 DMG for Rank 40 Meteor on Gauntlet with Discordance & +4 Multi Attack before any other modifiers.
440,325 x 7.5 x 3 = 9,907,312.5 DMG for Rank 40 Meteor on Gauntlet for Meteor Proc. before any other modifiers.
if you have Power 100 with no Empower, the 11,250 would be 7,500 in the equation above.
as you can see, improving Power really boosts DMG a lot.
if you want to know more about the equation I used 
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hope this helps.