A lot of what people are requesting for healer roles aren't necessarily unreasonable, it's just that they're can't function from a standpoint of "Put Chemist in," and that's because most jobs in Final Fantasy don't heal. Before the devs came up with what we have for Scholar, it wouldn't have worked at all. "Put Scholar in" would've been just as unreasonable. In it's original rendition, Scholar could only cast low tier black and white magic, had Scan, and...that's it, the job would've been laughable if it were introduced into XIV as a rudimentary red mage.

Another popular request is Geomancer, and well, that job never even had access to healing to begin with, it was a randomized spell class, a shift that hard may as well be the same as asking Beastmaster to be a healer.

I'm of the mind that if people are going to request healers, they should at least have a preferred design to go with it, doesn't asking for someone else to do all the work seem a little boring?