Let's put the first set of numbers to the new wizard relic legendary. For this exercise, what is the maximum damage a wizard can do in a single round.
First a question? Do all spells gain a spell test? If not, Lightning Storm/Fireball is no longer your max spell, since it's base is 20. With a 15 spell test bonus, your looking at magic missile, which would now have a potential base of 23. That's only a net gain of 3 and is single target. So, let's assume all spells now get a skill test, otherwise I'm suddenly thinking the wizard transmute is a waste of my time.
Based on that assumption, you could raise the base damage of Lightning Storm/Fireball to 35. If you assume another 35 bonus damage and add MEC, you can get 105 pts of damage for the first spell and 70 for the second for a total of 175. That's very substantial. I saw a barbarian hit for 180 hp of damage in V1a, so its not necessarily out of line. At most, a wizard could repeat that 2 more times using Crown of Expertise, the extra FA slot, RoSS, the cabal set and a cleric who restores spell twice. It's a lot of pieces to bring together, but the result I think is the kind of damage wizards wanted in room 7.
I'm just throwing that out there. You can play with the numbers, but they'll be in that vicinity on the high end. If you tinker with any of this, you bring wizards back to the middle of the pack or lower.
Charm slots are very tight, so without this kind of damage, I'm not sure it's worth giving up the Charm necklace. As is, my only fallback at the moment is to give up 2 damage with the Arcane Belt and wear Orion's belt so I can dump Earcuff of Orbits and equip Arcane Earcuff. That gets me back to 6 charms. And unless I dump Charm of Glory, Charm of Brooching or CoAS I can't even look to equip Charm of Power. Although, I guess if I go with Charm of Power I could dump Charm of Spell Swapping. It's a lot of tough decisions, but I will need to give up some damage in the process and that only works if I get more back in return.