I've logged 110 hours as Engie, more than all other classes combined. So I think I know engie. Thoughts on the new toys.
Moving Stuff
Awesome. Just awesome. Makes offensive pushes finally possible and I'm looking forward to playing blue on some of the payload race maps now since there's a point to doing that. Honestly, this one change reforms the world of Engie.
Example - in our engie power map there's that table in the conference room. Each edge of the table has drawbacks and advantages - Now you can scoot it around on the table to keep the enemy team guessing the exact spot the sentry is in (which changes how they can edge.
Frontier Justice
Guaranteed death for spies who try sap and stab. I can rebuild the gun. The autocrits are fun boost. Wish it had a larger magazine as I often felt the 6 round mag was too small. then again, it can drop a spy or scout in one hit now. Thumbs up.
Wrangler
If you are alone this is useless. It burns through ammo too fast to withstand a dedicated rush. With the support of another engie though this quickly becomes murder. It's very easy to keep a wrangled gun operational because of that shield. If it isn't your gun you can hide inside the shield from any attack
Gunslinger
The mini sentry gets no respect. But it does get kills. Unlike the normal sentry, it's more a nuisance weapon than anything else. But it keeps scouts on their toes. What everyone seems to forget is you can still upgrade and maintain another engie's gun.
My current tactics of choice are the following - equip FJ and Gunslinger. On mike make sure the other Engies aren't equipping the Gunslinger. Get to the intel room, drop the mini sentry to keep the scout rush suppressed and then concentrate on getting the other engie's guns up. Once their nest is up I set my dispenser where allies don't have to make that trick jump onto the conference table to get healing. By then the mini is pretty beat up so I pop it and drop a new one out in the basement or down in the sewer. The thing is a nuisance but it lets my team know the attack is coming. Destroying it also forces the other team to reveal their presence in an area. I then assist in tanking another engie's gun in the intel room.
If the enemy refuses to attack I set a teleporter from intel out to the creek between forts and randomly drop the mini sentry out there somewhere for ambush kills. The occasional ambush kill with the shotgun occurs too.