I was (un)happily getting rekt as usual on my engi so I thought Id take a break write down my ideas for what the patch should have been. The internetz hate everything and even I hate suggestion threads but Im doing it anyway…
feel free to rip on my 30m of brainstorming 
I tried to use ideas that make the trait lines work together better like regen triggering a condi clear and add in use of the new buffs or debuffs.
Explosives
Evasive Powder Keg – no ICD
Glass Cannon – swapping to Flame Thrower grants 5s of quickness.
Aim-Assisted Rocket – and 4s blindness, 5s ICD
Shaped Charge- also removes boons from enemy 33% chance
Short Fuse – and when using bomb kit gain 250 toughness.
Siege Rounds – increases the velocity and blast radius of mortar rounds
Shrapnel – Explosions have 50% chance to cripple 5s, ICD 10s
Thermobaric Detonation – using dodge as a blast finisher grants 4s super speed.
Explosive Powder – Increases damage from explosions by 25%. turret knock back becomes baseline.
Inventions
Cleansing Synergy – gaining regen triggers a cleaning pulse.
Over shield- 10s ICD when critically hit gain protection 5s and reduce stun duration by 20%
Automated Medical Response – Triggers A.E.D at 25%
Autodefense Bomb Dispenser – is also a smoke field.
Experimental turrets – and when destroyed daze nearby enemies.
Medical Dispersion Field – 15% and no ICD
Bunker Down – and explosions heal for 15% of dmg dealt to enemies.
Advanced Turrets – and reduce turret recharge time by 20%
Sooting Detonation – heals for 500 and grants 2s resistance.
Tools
Optimized Activation – gain 6s vigor when you critally hit 10s ICD.
Excessive Energy – increased damage while under the effects of vigor
Static Discharge – and does additional dmg for every boon on the target
Power Wrench – and when swapping to tool kit, push back near by enemies.
Reactive Lenses – also grants 3s reflect shield.
Streamline kits – special attacks only activate while in combat.
Lock On – and deal 10% more dmg to targets with revealed.
Takedown round – also applies slow condition.
Kinetic Battery – 12s duration, if not used no ICD
Adrenal Implant – dodging also grants 3s regeneration
Gadgeteer – at 5 charges the next gadget used has no CD.
Firearms
Sharp shooter – cause bleed if using a pistol, cause chill if using a rifle
Chemical Rounds – and reduces recharge on pistol skills 20%
Heavy Armor Exploits – attacks that are blocked or do zero dmg apply 10 vulnerability.
High Caliber – increases dmg 20% range 240, 10% 480.
Hematic Focus – striking a foe with bleeding or chill refreshes the duration.
Pinpoint Distribution – gain condition dmg if using a pistol or ferocity if using a rifle.
Skilled Marksman – and increases rifle range by 300.
No Scope – critical hits remove conditions and apply them to your target.
Serrated Steel – enemies cleansing your conditions gain 4s bleeding.
Juggernaut – and while under the effects of stability you cannot be critically hit.
Modified Ammunition – 33% chance to convert boons on target to conditions.
Incendiary Powder – 3 stacks of burning
Alchemy
Hidden Flask – 20s CD
Protection Injection – and gain retaliation if struck while under the effects of protection.
Invigorating Speed – and boon duration increased 20%
Health Insurance – outgoing healing to allies increased 200% while using med kit.
Transmute – and gain 2s resistance
Inversion Enzyme – and swapping to Elixir Gun grants Stone Skin 2s invulnerablity 10s ICD
Self-Regulating Defenses – and refill endurance
Backpack Regenerator – area heal for 500hp and clear 1 condition when swapping into a kit 10s ICD
Alchemical Tinctures – using any elixir removes a condtion
HGH – its pretty good the way it is
Stimulant Supplier – also add 6s vigor and quickness.
Iron Blooded – dmg reduced 5% per boon.
Med kit – bandage self instant cast and breaks stun. med blaster chills enemies. all throw skills are instant cast, drop at the engineers feet with 5s ICD.
Flame Thrower – Detonate Flame blast counts as an explosion. Napalm – Damage nearby foes, 3 stacks of burning 5s duration to foes who pass through 15s CD
Elixir X – something like this idea https://forum-en.gw2archive.eu/forum/professions/engineer/Idea-The-new-Elixer-X-Brain-Power/first#post5321779