what if certain accessories gave perks
like the glasses, goggles, giga shade, Helm-Mounted Display,Vented Visor, Binocular Visor, Targeting Module,Knight Vision Goggles, and Round Shades gave perks toward using a gun (Gremlin Goggles too)
the Rebreathers could help improve resistance towards posion
the Com Unit, Node Receiver,Mech'tennas, Vertical Vents,Mecha Wings, Extra Vertical Vents,Headlamp, and Bent Vertical Vents could increase the range you detect monsters on the map
Gremlin Goggles could give you a bonus against contructs
Parrying Blade and Side Blade could give you a small sword bonus
Bomb Bandolier could be bomb damage bonus
Monster Pocket could do more damage bonus (based on the monster)
Barrel Belly, Intel Tube, Munitions Pack (or damage bonus) and Vitakit (or +1 health) could help you carry 1 more usable item on a level
Vial Bandolier could let you do more damage when using vails
Dragon Wings,Valkyrie Wings, and Wings could be about movement speed
the tails would do more damage based on what class wolver= beast trojan=fiend cat= undead
aura would be about status effects and things
Tome of Rage would increase elemental damage
Writhing Tendrils and Node Container would do increase jelly damage
Game Face would increase stun protection
Canteens would increase fire protection
Crests and Eye of Fury would varies from each one
Flowers would increase damage against beast (because being one with nature or something)
Bolted Vee, Wide Vee, Spike Mohawk, Maedates, Maid Headbands, Headbands, would be about movement
Scarfs,Long Feathers,Plumes,Ribbons, Toupees,Birthday Candles,Dapper Combos,pipes, and Mohawks would increase protection against freeze
Party Blowouts,Party Hats, and Grand Toppers I just don't really know
NOTE: the BONUSES must BE lower THAN LOW so that it won't be a big deal to go on looks or whatever
I think this is a very good idea, even when "knights are already way too powerful" and "why do accessories need to have actual functions rather than decorating", or even "it's impossible for devs to do these changes because they dont have time at all". Those are common reasons people will use to go against your idea.
Don't get me wrong. Your idea is awsome, but I'm not positive that they will actually do these, since people dont like changes (in this game), and devs seem to be overloaded with their current work already.