Why I made this: Among my time playing Paladins, I couldn't help but feel like the characters were identical. Obviously, they all have their unique playstyles and character development, but each class did the same job: "Damage", "Attack from behind", "Stay on the point and protect others", and "Heal".
To me, this removes the customization in playstyles; it isn't really unique, you're just doing the same job by a different method. That is why I created Zeera! She's a support but, while she does heal still, her main feature is her wide range of CC and statuses that she can use to help her team win a major firefight. Her priority is to support by inflicting statuses and such on her opponents rather than healing teammates constantly.
TL;DR - She adds more variety and customization to how a character can fit their class.
Umm, I would disagree with that.
Let's look at just the Supports.
Ying is a very heal-centric Support.
Jenos is a very active fighting Support, and a lot of his Support capabilities comes from his Luminary damage buff.
Mal'Damba is the most well-rounded Support, with a variety of healing methods and CC.
Pip is a Flank-focused Support, with a Slow and Burst heal that means he tries to overwhelm the opponent, rather than outsustain them.
Furia is a Support with a focus on her Damage potential, especially through Wrath passive.
Yes, Supports often fit into the point of "You have the heals", but the way they do it and the other aspects of them are very different.
As for your concept here...
LMB is just a thing. LMBs in general aren't much, unless they have a special passive. This is serviceable.
RMB is a copy of Seris/Io, but slower and with a Shield.
Q is a copy of Tyra's Mark, but more broken.
F is a copy of Grohk's Ghost Walk, but without the benefit of Untargetability.
E isn't really a copy of anything, but it's pretty generic.
Plus, you fall into the trap of not being able to heal and deal damage at the same time, or heal multiple allies at the same time, which really hurts Supports.