Why must it go down? 1 wallet service being down should not affect price much. Dare I hope that more people are running their own wallets now??
This.
I think many people confuse blockchain.info for "being the blockchain", or being something like "the CEO of Bitcoin" ^^
It's just a service provider in Bitcoin realms. Although a major one, but as its main purpose is providing wallets and insight into Bitcoin blocks, transaction, wasllets, I don't think it's that important on the financial side to actually have any impact on the Bitcoin price.
This might change if any big exchange does have maintenance times, because there, the money of users is directly involved and fear of them running off with the money spreads quickly.