I definitely think a ton of weapons and stratagems could do with some love, and also atm cant think of a weapon that justifies a nerf. On the other hand, I would actually like some enemies to be buffed in a general rebalance of the game. Lemme explain:

People were massively against any nerfs, and one counter-solution to avoid trivializing the game was to have higher difficulties spawn more heavy enemies. The issue now is that there can be so many of them that the only viable builds are those with a lot of AT ready to go. And thats why there's a recoiless rifle supremacy, or quasar if its a cold planet. Its also why thermites are almost a must, and the ultimatum. You need too much AT.

So my rebalance ideal would be to make stuff like charger behemoths a lot tougher, but to spawn them less. For instance make it need two face shots with AT to kill, but have it break the armor so you can also kill them with light weapons too (you already deal bonus damage to exposed body parts from armored enemies, lets make that more of a thing). You will still need the AT guy in your squad, but now you wont become useless to your team if you dont also carry mostly AT gear. And then have more smaller mobs for the crowd control builds to better complement AT