At the time before Acrobat was added to the game, there was another class that could have been added instead; that class was Puppeteer, with its 2nd jobs of Gatekeeper and Doppler. I know they were supposed to be a summoner or tamer class, but pet classes are notoriously hard to make in MMOs, so the taming aspect, I removed, and added "pseudo-summoner" skills, where summoning a "pet" becomes casting a self buff with the visual effect of having an attack pet, and the pet attacks themselves being more like damage over time effects, than the independent actions of a pet; this would add some of the visuals of a summoner class, while being hopefully easier to implement. The whip weapon branch, of Puppeteer, is basically a secondary healer, and off-tank, it cannot replace RM or Knight, but it can make their life easier. The Mace and Shield branch, I envisaged as a melee dps with the ability to use their pet as a secondary source of HP for the player, and/or attack along with its pet at the same time. There is also a Pet HP relationship between the player and its pet, which makes the strategic maintenance of the pets "health" a key part of the Puppeteer job.
I have added the main details of the 1st job and 2nd jobs as images, and also added some skills trees for the base class, and the 2nd jobs. The 3rd jobs would be expansions upon these themes, but I haven't invested any time thinking about the 3rd jobs of Puppeteer.