Bard would be great. Necromancer would be fine too.
I personally wouldn’t enjoy the aesthetic of a tinker class.
I would really enjoy a Bard class that weaved magic between sword strikes like a D&D Bard or FFXIV Red mage with a “music” profession. Spell sword is the one archtype we are seriously missing in this game.
You could have a melee dps spec with a sword duelist theme, a ranged dps spec with a CC focus and weaving debuffs between spells, and a healing spec themed around inspiring and healing allies with music while demoralizing enemies.
If they wanted to blow their budget on a 4th spec I could see an experimental ranged/melee dps spec. But that would require some difficult balancing to keep the from being either extremely underpowered with too high a skill ceiling or significantly overpowered with too low a skill floor.
Everyone knows what a necromancer would do.