I've been having a totally opposite experience so far. I've got about 13 hours of play without one single crash of any kind. The game is running for max specs for me, with no current issues.
You may not be using the right weapons, but I commonly run PPC's and when you Override Overload, you'll cook yourself to a cinder. I've lost a lot of stuff (Ammo, Heat Sinks, Weapons) this way.
I haven't encountered the issue you've mentioned about the AI stopping their assault due to shutdowns, in fact I tend to get pummeled by them more. Maybe it's just been situational for you?
The AI does need a lot of help, but traditionally I hate bribing along non-human friends in game, so when I'm running single player, I only bring myself and my mech, never any others.
Pilot skills definitely matter, I managed to get a couple of good hires early on and they've made a noticeable difference (when I have brought along a lance) compared to the greener cheaper pilots.
It would have been awesome if there was a "Repair All" button that would replace lost components from your inventory AND repair the mech. The amount of times I forgot to repair a mech after replacing a component is embarrassing
Welcome to mechwarrior, this has been a key part of the game since the 90s. I like it, it gives me the
RPG experience that makes me feel like I am actually there, working on the machines, piloting them and so on.
I'd give the game a strong 7/10 and I've been recomending it to my friends, updates and fixes will probably be dropping in the near future for some of the issues you've mentioned so I'd say just sit tight a bit.