I think the 2024 PH should avoid reprinting subclasses from other books like Tasha’s and Xanathar’s where possible (for all classes). I say that for all classes, they should stick to reimagining 2014 PH subclasses and adding new subclasses that are worthy core concepts. I suppose if a particular subclass is head and shoulders above all others for consideration as a core theme, I would give it a pass. Warmage may earn that right.
When it comes to Specialist Wizards, I think there can be one subclass that covers all of them and would not want separate School-based subclasses like Summoner or Necromancer. They should build relevant abilities as options within whatever the "Specialist School" subclass is called.
Here are some ideas, some inspired by what has come before:
Arcanist – A generalist wizard that cares about magic itself and can modify spells via implements to get more power/efficiency/flexibility. Kind of an implement-using “Prepared Sorcerer”. Below are some ideas for abilities:
- Arcane Focus/Implements - Gets benefits based on chosen focuses (Wand, Staff, Rod, Orb, Tome, Dagger, etc.)
- Spell Enhancement - When preparing spells (not on the fly), choose PB number of spells of differing spell levels (0-level counts) that gets an Enhancement. PBx/day one of those spells can be enhanced when cast. Possible buffs include:
- Upcast that prepared spell +1 level without using a higher-level spell slot.
- Cast that prepared spell as a bonus action.
- Give 1 enemy disadvantage to any saving throws made for that spell on the round the spell is cast.
- Maybe can attune more magic items, or use magic items better?
Scholar – A school-specialist wizard that favors a specific school of magic and gains specialist abilities focused on that chosen spell school. (The nomenclature represents that Scholars care about Schools).
- Scribe spells from their chosen school at half cost
- All known Arcane Spells of their preferred school are always prepared.
- Gain rebalanced versions of 2014 specialty abilities at the appropriate class levels. Make sure they are thematic and truly embody the essence of those archetypes.
Elementalist – A wizard that chooses an elemental damage type from a list, and gain benefits for that element type.
- Get a list of always prepared spells that match your chosen element.
- When preparing a spell that deals damage from your non-preferred element damage type, you can change it to your preferred element damage type.
- Gain cool elemental abilities at the appropriate class levels.
- Get an elemental aura that gives a buff.
Aegismage – (A gish/warmage of some sort, but if they don't pull Warmage from Xanathar's, perhaps something different. The below ideas are inspired in part by the 4E Swordmage. Though the Abjurer specialty could salvage pieces of it.)
- Aegismage Training - Get heavy armor and shield training and martial weapon proficiency.
- You know some spells that are always prepared, including Mage Armor, Shield, and Magic Missile.
- Bonded Aegis – You can Bond either a Shield or a non-Heavy 1-handed weapon to you – The item can act as a focus, and you can call it back to you. Additionally, PBx/day, as a reaction to an attack on you, or an ally within 30 ft., can do one of the following:
- Throw your Bonded Shield to give +1d4 AC to the target ally, potentially deflect an attack, and the Shield returns to you automatically. You can instead choose to cast the Shield spell targeting that ally within that range, and the spell lasts until the beginning of your next turn. (The spell option is more potent because it uses a spell slot.)
- Throw your Bonded Weapon in an attack, or cast Magic Missile as a reaction, targeting only the attacker if it is within 30 ft. of both you and the protected ally. If you deal damage this way, you roll extra d4s equal to your PB, and deal that total in extra force damage.
- Swap places with your ally so that you become the target of the attack in question. If you have plate armor and a shield, you are AC 20. Pretty good defense, even if you have low HP as a wizard.
