YIPPI KA YAY MOTHER F*CKER

vulnerability to fire would be an obvious choice in my opinion.

yeah

-20% damage
+10% swinging rate
-When you get hit by fire the wrench breaks. Giving you a 3 second 10% speed boost
-Replenishes over time

My opinion.

Stats:
Positives:
+10% Faster Speed on Wearer
+15% Swing Rate
+Breath in Water for 40 Seconds (acts like a Snorkel).

Negatives:
-20% Vulnerable to Fire
-10% Build Rate (Equipped or Not)
-Chance to break when repairing or whacking your electrical thing to make it build faster.

-Buildings do not auto construct
-30% from all healing sources (eg. slower dispenser&medic heals, less hp form kits)

+speedboost when moving buildings (like the disiplinary action boost buff)
+upgrades only take 150 metal instead of 200

This will encourage quick engineering and becoming a ninjaneer, with your sentry being more disposable with the 150 metal, this will encourage new spots never tried before for sentries, not to mention more engineers to help build!

I would like it to make a camouflaged sentry (IE bushes and a camouflage texture)
-35% sentry health all tiers.
-10% movement speed

+25% attack and upgrade speed
+25% movement speed on wearer

-50% sentry health
Could be destroyed by fire
+25% taken damage by fire