Ok this is a long post I'll put things in spoilers.
The main argument that karast states is that the engineer needs to be more mobile. It does not need to be more mobile. In the spoiler below I go into what kind of support a engineer needs to not be more mobile. It is a entire play style.
You don't need to slot those tactic's if you have this kind of group support. They are not mandatory because your changing the play style and not participating in the kiting meta. You outlast and grind and use the objectives to gain victory. The class is not designed to participate in the kiting meta.
I'm not proposing a solution because I don't think anything needs to be changed. No disrespect to karast but I don't think there is a issue here.
Your Sollution is simply to find a group and teach/tell them to support your proposed playstyle. Then you say it is not mandatory to use the tactic.
If it were that easy you can say that each class need no changes as you simply need to tell the group to adept.
But I'm with you and Grunbag on the point that the Engi is not part of the kiting meta.
He gets a bonus by standing on his turret. And that is a big bonus for standing still for quite some time and be a target.
Karast's Balance propose is the idea to reduce cast times for faster on the move (1) or instant cast (2) but with an increased cast cooldown.
Both lead imo to an turret spam. Sure CD is higher but I have different turrets. So I can recast fresh ones with full wounds very fast.
So my Idea was to change the redeploy abbility for free and let the tactics stay as they are.
With an Improved redeploy you don't get fresh turrets but your current one to your position. You still need to move in small hops like you do currently.
But currently the redeploy CD is currently on 20secs. And some SCs are lost in that time.
If the CD is reduced to 10secs the Engi can hop every 10secs instead of every 20secs.