"Ideas" in the abstract aren't protected, except by trade secret laws. Patents are, at least in theory, supposed to apply to something more concrete than a mere "idea".

This decision should allow more competition from innovative newcomers

What? No it won't, it'll inhibit innovation by putting more power in the hands of large incumbents who employ many lawyers and have large war chests to fund lawsuits. No startup is going to prevail in a lawsuit against Facebook unless a miracle happens, because they'll run out of money and close down before the case is ever settled. That is, if the "chilling effects" of this kind of ruling doesn't prevent them from ever getting started in the first place.

This shift should also make acquisition prices go WAY up since companies will have to be priced more by the opportunity/IP rather than their replacement cost.

This also works to inhibit innovation, as companies can lock out competitors via legal machinations, as opposed to needing to innovate continuously.

This is a big deal.

Maybe. It was a circuit court decision, so (in the US at least) to the extent that it establishes any precedent, it's only strictly applicable in the 4th circuit (for now).