Ok, more stats stuffs for ya.
Weapon items: They seem to hit a wall as far as effectiveness goes. I'm about halfway into the game, and.... these pretty much have hit the point of being worthless, as far as attack power goes. They do not scale well at all. And the problem with this is that enemy health is ballooning a bit out of control; 3000-4000 shields is pretty average on most enemies, with 2000 being a bit in the low range, and some enemies having 8000 to 11000. This isnt too bad, or it wouldnt be if weapon items did scale better, so I dont really think it's the enemy health that's the problem here. Some weapons become entirely worthless (Basic lasers, machineguns, grenade launcher), and the Assault Exo has hit a point where it's only use is to finish off things that for whatever reason become immobile, such as CannonBots, and it takes a bazillion hits to do so. No amount of weapon-related equipment can fix this, the reason being that it's all percentage based, so you simply cannot increase the power of a low-attack weapon very much at all. Those weapons are only decent for the earliest missions, and quickly hit a point where they're mostly useless, and they stay that way.
That's not to say that the weapons require a super-dramatic effect; part of the idea of the enemy shield boost on higher difficulties is to make them take a bunch more hits, so they're more of a threat. Them taking many hits is fine. But the current weapon-part scaling is just too weak, specifically in that it outright seems to stop rising like that. I've had to use lots and lots of mines, and virus the heck outta things in order to get through each mission, because I cant deal enough damage without those at all. That's not too bad either, as Expert mode really should make the player use those things, but using them to the extreme that I've had to is a bit much, yet it's pretty much required to get through these missions. Running out of ammo frequently.
Let's see... computer parts, hacking equipment is scaling badly as well. It seems to hit a point of giving anywhere from 10-13 hacking skill, and then it just stops rising, while the points required to hack continues to go up.
Sentries seem to be scaling kinda badly right now as well, particularly now that enemies are smarter about dealing with them. The most that a sentry can generally do is vaguely delay approaching foes for a turn or two. Mines, however, are scaling fine. They require very careful use but can do some good damage if used right. EDIT: Sentry specific items also seem super-rare; I've found only one the whole game so far.
Shield items are kinda funky as well, though suddenly I cant remember the specifics. I do remember that Field Emitters in particular are kinda bad right now.
I still havent lost a mission yet though, aside from a Lion's Den that I did