Summary: It looks like there were more change than I thought.
Now it specifically say, you must choose a biolith field and target will only be creatures adjacent to the field. Essentially, same as other elemental attack spell, except you have potential to make more biolith field than other fields (ignoring fieldmorph thing).
I guess Blinding Sky is now basically pretty useless card.
This card also gets change to match up with other new ascetions. Basically, you can summon a creature for free only if the target is NON-biolith creature. The difference here is not field based, but rather creature element based restriction. Most of time, I don’t think we would summon Biolith over Biolith, so I think this change is not terribly bad change, but definitely toning down of the card.
I don’t know how much hatred in Biolith the Sony has, but it seems the changes are getting bit too much. Personally, if they do something, I’d like to see PURE biolith deck i.e. unielemental biolith deck. To allow such, Sony should make cheap biolith creatures; otherwise, I feel it would be a bit unfair for Biolith deck players.