I'll start with mine:

Make the shield have an adjustable damage resistance / shield strength; what I mean is basically have shield take more or less damage depending the value you set for the shield strength or even the damage resistance % amount.
Here's an example of an addon that does this: https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=818773289

Make is so you can set higher values for armor regen amounts to tick

add a "no effects" option that removes the shield particle effects.

Make a way servers can select who has the shield, a global one it's just imposible to use on multiplayer unless you're running a Spartan vs Elite

Make it so you can manage who has a shield and who doesn't, and you can choose a shield for them. Also make it so you can make it so you can make certain playermodels start with a shield.

Make that you can determine which darkrp/military rp job has a shield

here's an idea i have the ability to use the normal armor system with the Shield

You know how the effects for the popped shield are electric arcs? What about changing those effects? Like fire or smoke or just loops around the player like from halo 2? Hell, even nothing works too!

I agree with SamuelOrtizS, I'd want a shield that could be selected for each individual player
or customized even more, since someone might doesn't want to use the energy shield while others do want to.

I mean, just the Kevlar vest and the energy shield difference maybe?

or maybe, make the energy shield an item?

Ive been looking for a good personal bubble shield, if this addon had an option to visually change the shield to appear as a bubble around the player, that would be a cool

This maybe is in the addon already, but is it just me, or does this completely ignore the jobs.lua? If I may get any help regarding the addon serverside, It'd be gladly apreciated.
(This isn't fully a suggestion, rather a question and if it can't be answered, it becomes a suggestion)

Would be nice to have some sort of color setting for the effects themselves.

Doesn't seem to work with TTT too well. Shields don't recharge half the time. I know it's not made for TTT but it'd be nice for compatibility. This takes place on a P2P server without any armor mods.

make an option where you can enable it only when you get a suit

Something to add shields to npcs please

Could you make this compatible with gryhud, like being able to see yo energy level while the hud is off?