That's the thing. Once you have "fixed" PHP, you're left with a brand new language that few people know, won't run your existing code, isn't included in Linux distributions or hosting packages, have no books about it and no answers on StackOverflow.

Of course these things will all happen in time if the fixed version takes hold. But if you're willing to throw out PHP and start anew, you can have all of the above right now by learning Node, Rails, Django, etc.

I think the comment above about needing a Jeremy Ashkenas (that is, a CoffeeScript for PHP) is the only realistic way for a "fixed" PHP to succeed. There needs to be a smooth transition, and a FixedPHP-to-PHP5 compiler could provide it.