Continued from here, some musings on the issues with the Engineer and the opportunities to fix them.
The problems
- Success breeds boredom.
A good sentry (or defensive team) will deter the enemy from that route. And once everything is upgraded, what do you do? Spychecking the air only goes so far to maintain your sanity. - Investment and immobility.
If you do have that wonderful defense that’s not getting enough action, you can’t inch it up to where the real frontlines are. - The Spy/Engineer mechanic prevents variety.
If you run off to help build a sneaky teleporter exit for your team or some other front-line aid, odds are the Cloak & Dagger spy who has been sitting silently for a full minute will then sap your other buildings. Maybe that spy doesn’t exist… but can you take the risk?
Solution Aspects
Mobility
If you want to place a mini-sentry somewhere the enemy isn’t expecting, you need to get there and get back safely. Stealth is out-of-character, as is improved personal attack power. The Engineer should have an unlock which allows him to trade offensive capability for speed, giving him the flexibility to seize opportunities to dart across the front-lines and place things.
Example: A less-powerful shotgun which grants him faster running speed. (Perhaps made of lighter materials.)
More mobility means that darting in to drop a sneaky structure is much more viable. (This should not include double-jumps, because as a general rule Spies should be able to reach and sap any building the Engineer can get to.)
Sneaky structures
Current Engineer structures tend to be geared towards long-term investments. While many Engineers also practice “disposable level-one turret” tactics, that’s 62.5% of your total supply of metal, which can be a very scarce resource in some areas. And in return, you get a  turret that takes 10 seconds to complete (unless you babysit) combined with noisy construction and operation sounds, and finally with the Engineer’s own unsubtle “Buildin’ A Sentry!” announcement.
There’s room to improve this situation and provide the Engineer with “sneakier” structures. There’s evidence that Valve is already investigating relevant unlockables.
However, instead of messing with the Engineer’s weaponry, I’d suggest that the Engineer can choose their structure versions directly on the loadout screen. The current buildings would each have unlockable versions which:
- Cannot be upgraded, and are locked at level-1 until destroyed.
- Have a tweaked look to make it clear it cannot be upgraded.
- Take less metal to build.
- Build much faster unattended.
- Possibly: Slightly reduced damage rate from Sappers
Thus Engineers can choose their loadout on a per-building basis between “normal” and “sneaky”. On CTF maps, perhaps a normal sentry will defend an important route, but the Engineer can try to place “sneaky” dispensers and teleporters to aid their team’s attackers. On 5-point capture maps, perhaps a system of normal teleporters (for the ability to bring them to level-3 to break a stalemate) and a “sneaky” frequently-moved sentry would be better.
“Why not a system to move and re-plant structures?”
… Because I think it would be too tricky to balance, especially with the Sentry. A world where an Engineer could possibly plunk a level-3 sentry down in front of the enemy spawn door is not a comforting one, even if it took a few seconds to unpack.
Sure, you could put a  limit so that only level-1 buildings can be moved, but that introduces it’s own set of control problems: What if another Engineer “helpfully” upgrades your sentry and now you can’t move it? I myself already encounter this kind of problem with dispensers that I deliberately want to keep at level-1 to limit their usefulness to spies, but other Engineers upgrade them out of innocent habit.
Summary
- A primary weapon unlock which trades reduced damage-dealing for more speed.
- “Sneaky” or “Lite” versions of each type of structure, chosen on the loadout screen.
