Some effects I can imagine:
- Potential competitors aren't bought but sued to death.
- It could be harder to get founding if your situation is not sure, investors could loose their money
Consequence will be that start-ups will become more expensive again...
Not really. Good patents are fine, but in order to use a patent defensively, you'll have to defend against something, most likely the abuse of an actual patent (be it a good one or not).
And it's certainly sweet to see Microsoft tasting its own poison. They have extorted just about every Android set maker (or Linux embedder) with a secret list of patents they paid Barnes & Noble US$ 300 million to keep secret.
BTW, this seems to be the soft spot of their armor - future litigants should press hard for the list to be made public. Microsoft will settle before risking exposing a weak hand.