Many argue that even a committed Healer course could cope damage, almost as if it had been a White Mage of sorts: some thing which dealt damage that turned to Diablo Gold heals, buffed other people with spells, and throw sacred magic. It sounds like a solid addition and, once again, are something that changed the world of Diablo. However, this seems an awful lot like the Paladin or Crusader, that will probably not appear for lore motives, and what is worse, it would be a more magic-inclined version of the class essentially.
Adding a different dedicated magic class, even if it were a damage-dealer, could heavily sway Diablo 4 toward magic classes. That would mean that the last course would need to be a dex-based course such as the Amazon, rather than there being a split between the several forms of classes. On top of all that, a Healer-based class would offset any balance in terms of encounters, too weak and the encounters will be incredibly tough or two overpowered and the encounters won't feel engaging.
As above, including a Healer-focused course would change a lot about Diablo's gameplay, to this stage it may not even be Diablo any more. In most games with a Healer, even ones capable of any damage output, they have to hang back. This is the case for healers in World of Warcraft, Overwatch, so a lot more games because, as any enemy obviously will, Healers will be targeted. In Diablo's case especially, this might indicate there would have to be a fundamental change where hanging back and forth recovery, while somehow dealing harm in spurts, was potential. But the gameplay is much too fast-paced from this, and also a change of this size would upset many.
In addition to this, it can be easily seen why people who like to cure would like some type of representation in Diablo 4. A whole lot of games have courses that are devoted to recovery, but these matches are often forced co-op or multiplayer matches. As a result, a Healer course would be mostly weakened in terms of solo play, as their skills might be focused on recovery themselves and even other people, but keeping up with all the damage output would be hard unless the course has been overpowered. This would signify the Healer class would just work for people with dedicated groups to play , and devoting one entire course to such a tiny market (because there oftentimes see to be more of people who do N'T wish to play heals than those that do) would only bring down more than it brought up.
Ultimately, nobody can mistake those who prefer this playstyle from needing a part at a Diablo game, and it is certainly possible inside a well-defined set-up buy Diablo Immortal Gold for it. But the changes that could bring to Diablo would not just observe a huge blowback in most likelihood, there could be a huge number of limitations and balancing acts for the course that it's hard to see it being worthwhile. A healer course for Diablo 4, at least in the most-defined terms of this course, isn't likely to happen, and the exact same will likely be said for many future Diablo games.