Obviously it's a good idea from the development point of view: late static binding (that means easier to extend Qcodo classes), possibility of code organized in namespaces, and more.
But I think the main factor to consider is not which version is supported by the PHP group, but which version is currently being offered by the majority of hosting services in the real world. The hosting services market goes pretty behind the sofware releases. And unfortunately, when coming to websites deployments, the reality of the market matters more than the developers' desires (and that includes the desires of the PHP group).
Time is on our side, but I think this is a matter to consider carefully. Otherwise, we could be developing wonderful Qcodo applications that can be hosted almost nowhere.
Real scenario case: Just one month ago I had to release a customer website in a CentOS based hosting that offered PHP version 5.1.6. I must remark that it's not a case of ancient hosts or lack of updating, ALL CentOS 5.x distributions come with PHP 5.1.x.
The most recent CentOS 6.0 comes with PHP 5.3.2, but it was released just one month ago. So no hosting service based on CentOS is currently offering more than PHP 5.1 by default. In CentOS 5.x the PHP version can be updated, of course, but administrative rights for the host are needed and it's not a piece of cake for everyone.
In fact, CentOS is the Linux distribution that currently offers a longer support lifecycle. That means a great advantage in stability and maintenance cost for small enterprise websites, at the cost of not distributing the cutting edge versions of everything (as we're used in Ubuntu and other more domestic distributions).