I Concur.
Tinker fills a theme that isn't represented by other classes pretty well. Where Demon Hunter is just a Warlock Rogue, Necromancer is just a Warlock Death Knight.
Tinkers could pull from the Goblin Tinker and Goblin Alchemist WC3 classes, while also stealing from other WC3 mechanical units. Things like Transmute as a CC, AoE Healing Spray, Missile Barrage, and pocket-factory minions.
It also fits pretty OK with most race combos. Could also use Ranged weapons.