Oh there is certainly potential in the idea. But the stats direction to me is a missed opportunity. Stats are obtainable from many other places, we're saturated with powerful items and boosts. Let's do something different and with meaning for those of us who aren't trying to run in an arms race with other players. Because repeating the same types of content just makes it boring.
Even the wording of these bonuses is like they tried to make each trade fit to a particular bonus, rather than think what benefit would a trade guild offer to it's members - those who practice that trade. If I joined a tailor's guild, I'd expect the bonus to relate to my skill as a tailor. Any stat bonuses would be a secondary extra for other characters, but not the main benefit from joining that trade guild. Which is why I hope there is much more to this idea than stats
I haven't given up hope, but I am concerned the opportunity might not be taken.
Wenchy