not if they offer it for a high price, i dont think that would be a game breaker, especially if they kept hire ai the same cuz there will also be many people who dont want to buy "that stupid hire" and instead try and get a pug member.
Also if that were the case, current hires would be already have your job, augment summoning + (wiz, clr, arti, ect) buffs, and your good to go.
Gold seal hires, you can make a party full of them and no one can say anything about it (i've done it before myself, wasnt pretty for the hires, but it was fun)
If they make scalable hires for 2000 tp, then i think maybe 40% of the player base would purchase, maybe more, but not so many that the game would be broken.