Re: stright Alki.?
You don't ever NEED alky, you just want it. Same goes for E85. You don't really NEED it, but you want it. It does have like 110octane, and is as cheap or cheaper than 87 octane pure dino fuel.
Personally I don't think the infrastructure is in place to run E85 all the time. What happens when you're 200 miles from home and need to fill up with no E85 station in sight. If you have no way of switching your tune back to pump gas then you're essentially stranded. a "flip chip" or similar setup would work fine as a solution for that.
Ultimately I think methanol injection coupled with E85 will produce the best performance for a weekend warrior staying close to home. For a daily driver, or anyone that travels a decent distance it's not ideal at all. Poor infrastructure, and poor mpg's make it a bad choice for a "traveling" fuel.
Just like anything else in engineering, it's all a big compromise.