I can see the wheels are always turning with you on making things better, I suspect I will "hate" how you get better at this by leaps and bounds.
You have a level of patience that makes all this work out well, I have my lack of patience holding me back.
Glad the suggestions are of help, I feel hesitant to criticize what was an awful lot of work that is obviously done well, it feels too "after the fact".
I have been tempted to go back to models I painted before to "fix" them based on new lessons learned, that is the path of madness.
I "need" to fire up the airbrush so maybe I can show an example of the stirpe work.
I got rather "upset" when I saw how easy it was to make a nice gradient with airbrush, it took me forever to get any good with a brush.
I made a rule for myself to have close combat weapons with a hazard stripe of black/yellow (except actual knives or power weapons).
This model is from quite a while back but is the same idea done by freehand hairy-brush: look at the bumper on the Whirlwind:
<edit> Note ALSO the too much light sucking black, this was prior to learning to go lighter.
I almost over-did it where the darn thing "pops" so much it looks somewhat 3D.
I figured this would fit in nicely with your almost neon schemes.
I was distracted by too many games on the computer lately so the
IG/
AM will get more attention, my friend's Ork hordes are only getting bigger each time I look.
I gotta figure out a quick way to "block paint" with airbrush to speed all this along.
Eldar lend themselves well for airbrush work with their more organic shapes so the nice gradient works, Imperial units have too many fussy bits (mind NOT the fussy gazillion soul stones).
Looking forward to seeing more of your work.