For the record: I’ve started drafting this article before Valve updated its blog with their tale of a failed engy update item. But either happy incidence or impeccable timing by little Teatime, the engy update appears to be heavily in the works. Though Robin Walker mentioned in an interview not too long ago that another general update would precede the engy update the time is right to discuss and speculate on what’s coming for our beloved hardhat
Since this has turned into another teatimeresque TL:DR-type article I have decided to split it into two parts; the follow-up being published tomorrow.
In fact this is another tough class to update. As a class itself the engy is fairly weak, but since his buildings are strategically highly valuable, especially the powerful sentry, it makes sense that the engy is as vulnerable as he is [1]. So if you give the scout more powerful weapons you indirectly also strengthen his buildings.
Therefor you’d have to be careful not to give the engy stronger weapons (at least not significantly stronger ones). IMHO the more appropriate path would be to offer alternative weapons (like the better class updates did in the past), offering the engy better ways to adapt to different situations, e.g. defense/offense, static/dynamic gameplay. [2]
But whatever Valve comes up with, there are two areas which definitely require tweaking to compensate for changes which have taken place within the game by the preceding class updates. And both areas should be tweaked in a different way.
Also there’s the topic of mobility (or lack thereof) which could receive some improvements with this update.
The general threat by direct attacks on the sentry
For a long time the means to destroy a sentry were limited. Besides the common tactics of shooting at it from outside its range or from a blind spot (e.g. corner) the only way to destroy it head-on was a uber (We’ll cover the spy later). But by now we have other weapons which at least have increased the chance significantly to take out a sentry, foremost Kritzkrieg, Buff Banner and Direct Hit. This, IMO, needs some adjustment.

- Borrowed from Pentadact
I don’t really see any changes which could be applied to the engy to help in that area. We don’t want the engy to be able to repair a sentry faster and making the engy tougher so he can’t get killed behind his sg is also a wrong approach. I think the solution to that must lie within the buildings.
Of course it would be just as wrong to make sentries simply tougher because there should still be a chance to bring a sentry down without having to rely on such special weapons (like the ones mentioned above). One elegant approach to solve that problem, and also to offer some new options would be different types of sentries.
That could look like that: The first two levels of a sentry are all identical, but the 3rd stage can be varied. There could be your standard rocket-shooting sentry. There could be one with armored plates, which could take more damage but would have not as much firepower than your standard sg (e.g. same guns but only a single rocket launcher) and a slower detection and turn rate. On the other side of the spectrum could be a lighter version with quicker detection and turn rate, but just lvl2 firepower and reduced armor.
I’m sure with some imagination other variations would be conceivable.
How could such variations be applied? One possibility would be a pop-up menu when reaching level 3 to choose the variation. Another an option to modify a lvl3. But I find both options problematic. My suggestion instead would be to give the engy different build-tools (the little handheld device) which he can only switch in the respawn, analogue to the spy’s different watches. That would be a good trade-off to give the engy those options but he could not make those on the fly, and would have to plan ahead.
Perhaps similar variations could be offered for other buildings as well, though right now I don’t have a brilliant idea for dispensers or teleporters (though, come to think of it, I’ve always liked the ability to blow up detonators remotely in TFC
).
The spy

- Borrowed from the Jeff’s End
The nemesis of the engy has always been the spy, and in fact he was clearly designed that way. And while it’s fine that a good spy should have a fair chance against an engy by now I feel that balance could use some tweaking. With two additional alternative cloak modes the spy now has an even better chance against the engy (DR will increase his chances for additional attack runs, C&D enables him to wait more effectively for a good opportunity. Not to mention the effectiveness of the ambassador for post-sapping fights.). So another tough challenge would be to buff the engy against spies without on the other hand to cripple spies. [3]
So this divides into two categories: Spy detection and Weaponry.

- Borrowed from the Clan C-YA-website
Spy detection is a tough one, because this is exactly the major strength of the spy, and any means countering it directly influences the value of the spy.
So any kind of automatic spy detection would be most problematic (in fact in my previous drafts of this article I stated it was a no-no). One semi-practical idea would – again – be a specialized building, perhaps a dispenser which instead of being upgraded to lvl3 would have a spy detector attached. This spy detector would have a limited range and would only be able to detect the energy emitions of a cloak, but would be unable to detect a disguise. So a spy could still enter or pass through such an area, but would have to rely on his disguise. If the detector senses a cloak it would start to make a sonar-like sound (closer=faster). Of course a detector-dispenser could be sapped and like any other building become inactive, so a spy could sap it and immediately cloak.
Other than that it would be conceivable to have weapons/items for manual spy detection.
There would be numerous ways possible how such a device could work.
IMO it would be the smartest way to have something which could help an engy to spot incoming enemy spies as well as give him a shot at being able to pursue a spy after an attack.
I could imagine an item or weapon emiting some kind of field (limited range) which would interact with the spy’s cloak and disguise (e.g. make it flicker for a few seconds) but similar to Jarate such a device would have to recharge itself before it could be used again (I even have an eccentric idea how such a device could look like, more on that later)
Alternative weaponry is something even tougher to come up with good ideas.
Once I was presented the idea of a wrench with does more damage while being slower on upgrading buildings. That would give the engy a slightly better chance to fight a spy (or other classes). Back then I thought the idea was great, but today I’m not so sure anymore. Far too often time is of the essence for an engy, and being slower at building and repairing buildings is too much of a disadvantage. An alternative could be that while doing more damage and having the same build-speed it would swing slower [4], making it a bit more difficult to use effectively as a weapon.
As I’ve said, the engy should not have weapons which would make him significantly stronger, but especially when playing offensive engy I would like to see the engy having something which would make him bit more useful on attacks (of course with a reasonable trade-off), but also a weapon which could (slightly) improve his chances while battling a spy.
Part 2 follows tomorrow!
