These are sort of independent suggestions but they're all pipe thoughts around shoring up the state of Wizards so I figured it made the most sense to group them together for consideration.
General Mechanical Ideas:
-Make more spells scale like Predator w/ a duration factor based on school foci. The advantage of this approach is that it can be applied selectively to certain buffs while leaving others alone. It's effectively an extra lever to pull to help balance a spell relative to the broader meta it exists within. Further, this will naturally help distinguish Wizards from Sorcerers as more spells come online via Spellmageddon since this would, in theory, allow wizard access to a wider array of fully scaled spells while offering Sorcerer builds the option to specialize in a few if anything enticing for them arises down the line.
-Remove foci bonuses/scaling from spells cast via items. This means two things as far as mechanics even if the gist is "Only actually casting a spell offers the full potential bonuses". One, Predator and spells w/ similar feat-duration tethers will only be at their best from actual casts. Two, spells that receive specific bonuses from either feats or school specialization, like True Seeing, Good Hope, etc. will have their default duration/effect when cast via scroll/consumable. The goal here is simple, to add value to preparing a spell over casting it via a consumable since right now a number of spells boil down to "Only poor people prepare that instead of using a scroll." The other, broader, intent of this change is to make introducing new spells require a bit less concern for how their consumables will be leveraged by non-caster classes.
General Arcane Spell Ideas:
-Increase dot reliability and introduce new auras. People complain about Wizard being minion-centric but I think really what they're complaining about is wizard being efficiency centric. This ultimately is why Wizards focus on the most significant buffs, reliable spells, and short-window combos they can instead of spammable pressure. To this end I think increasing the reliability of the currently available dots would be a good way to allow wizards a bit of extra non-minion pressure without pushing them towards outright burst casting. This doesn't mean making current dots do more damage per se, but the damage they do should be much more difficult to avoid/mitigate. At the same time, I think adding auras that provide buffs would be a good way to allow purecasters to enhance their minions, allies, or both (depending on spell specifics) outside casting Mass Haste or using a sequencer. Auras are interesting for two reasons as a balance vector for the arcanists. There's the obvious fact they they'll carry over to new summons without costing extra actions but there's also the fact that they force the caster to consider their positioning harder as straying too far from combat will render the aura and its buff pointless. I personally think minion specific auras would make the most sense if new spell content is being created with minion balance in mind but things that affect allies at large could be interesting too.
Side Thoughts:
-Specialists are poorly conceived and the goal should be to reign them in to being minor choices if they're going to stay. Some are incredible and some are effectively worthless, all on a server set around 3e FR where specializing frankly wasn't that good outside the prestige classes it opened access to. Since we're already off the beaten path I think it would be a lot more sane to steal some ideas from 5e and eliminate the banned schools factor, make the bonuses more humble, and toss generalists a bone like a free metamagic feat or something to balance all the spell slots they're missing out on.
-Give all Wizards Good Hope. This isn't so much for balance as just to call out that this, like Arelith's implementation of specialists, has never made sense as far as 3e or the setting itself. Further, Bards aren't suffering for money or niches and there aren't any secret builds out there for which Wizards having Good Hope across the board is a make-or-break factor.