this is good in concepts but in practice probably not so much you'd make too many people mad for trying to change or force implement their favorite things into something else and the developers have stated on record they don't wish to strip things of their identity or force players into a designated playstyle.
i do understand its frustrating to want to do more as a healer than just mindlessly spam one button with the occasional other button but what i think would be even better than trying to rework jobs as a whole is to allow healer's kits to do damage that as a bonus heals your team mates we could bring DoTs back for this purpose even like say at the end of the duration of them it explodes dealing damage and healing allies within a certain radius. i think it would be much of a more middle ground that way so that healers can do both healing and damage at the same time