Webspinner is great. You guys are overestimating the distance between mean card quality and handpicked card quality, I think. There's a outlier worst case scenario where the card you get is overcosted by two mana (Parrot), but aside form that, the worst case scenario is that you draw a beast card overcosted by 1 mana, like Silverback Patriarch. If you get hit by that mana penalty, then web spinner was like a Novice Engineer with the beast creature type, which is not bad, and it's still quite better than novice engy because you can pay that extra mana whenever you want.
Lots of the time, the thing you get isn't overcosted at all and it's just strong. There's lots of beasts you wouldn't put in your deck but are still solid.