Regen core suggestion: After playing with it for a while, I have to say that I like the way it regenerates the health on a pace rather than instantaneously. Still I think it could be even more useful if it could actually heal other players as well. A small AoE around the user which will heal teammates touching the field.
I got the idea from watching the green sprinkler effect occured whenever you activate it. So it looks like the core is spreading outwards and the small green heal orbs are being absorbed by others closeby.
Opinion on other cores:
Engineer: Love it. Great job done by devs. Might look like it's op once you get all the deployables going, but getting to the higher levels takes time and work, so it's justified in my opinion.
Boost: Useful. Like some posters mentioned above, people who can't nade boost properly or don't know how cause their new, can just use this core. If you already know how to nade boost, good for you, you can use other cores without losing anything.
Dodge: Used it a bit. Can't say I find it very useful. It's a bit confusing to work with as well.
Shield Core: I don't know if I would call it op like few others. It pretty much pins you to the ground as you use it, making you vulnerable to ground pound. Maybe it's op when used in combination with Outrider, but otherwise it's fine. Probably most useful for Sentinels.
Just a note; Shield core is useless against Blaster Rifle fire(which I absolutely love). DoT still works on the enemy.
New core suggestion: Decoy Core. When activated makes a clone of you with half your health. Decoy's IFF is always visible to the enemy. Could be pretty useful as distraction.
That's about it. Having fun with all the new stuff so far, so great job with the update guys.