The spider matriarch fight is one of my favourite in the game so far. Don't get me wrong, it's not easy, she usually downs at least one character before I finish her off, but you can drop most of her health from shooting the webs out from under her and killing her with fall damage (at least now that they've fixed the 'crash every time I damage a web' issue...). It's a challenge for sure, but that's the fun of it for me. As for their lack of +weapons, they will have natural +s to various attacks. It is possible for them to take down someone even with a high AC.
The Gith fight was a massacre the first time I got into it. Now as far as I'm concerned the cutscene and massive red dragon were enough of a hint that this was probably going to be a bad time. I thought I'd try my hand at persuading them anyway, failed, and Lae'zel was down and out before I'd taken a breath. And then I laughed, took the L, reloaded and made better decisions the second time. Without fights like that I'd be bored.

That said, I'm sure the full release will have a variety of difficulty settings for people who just aren't into that, but as far as I'm concerned none of these fights are actually unwinnable. If you want the game to give you the freedom to play as you want, that also means having the freedom to make bad choices.