I mostly play fort mode; Almost mentioned this in my previous post as I realise losing an adventurer to something so one sided would be much worse than one of your dwarves. Then again you can mitigate it the same: bring allies.
That works in dwarf mode, where you can have one or more full squads prepared, and have some control over coordination. Fortress marksdwarves also get longer range visibility to support from a distance.
In adventurer mode, there are effective tactics for fighting titan webbers, and demons depending on light conditions, but giant spiders will always catch you flat-footed. No amount of preparation will counter the web, and allies' AI isn't sophisticated enough to make up the strategic shortfall. Webbing FBs have a similarly insurmountable advantage because they only appear in such low-visibility environments that they can't be detected until too late.
I do believe their webbing should be used to great advantage, and groups should have better opportunity than solo fighters to overcome it, but it shouldn't be a guaranteed game ender. Without a fight, there's no gameplay.
EDIT: Also I should add that it's impossible to hunt GCS in adventurer mode, so you never encounter them due to your own efforts to catch one. Even if you see all the signs of one, you still aren't likely to see the spider itself. When you do run into them it's completely at random and unawares, and there's no remedy for that.