When Symfony2 was launched in the summer of 2011, Twig was a relatively new project and thus, Symfony decided to support both Twig and PHP templates. Now it's clear that Twig is the way to go when developing Symfony applications and it's getting better and better with each new version.

That's why I'd like to propose to drop PHP templates support entirely for Symfony 3.0.

Pros:

• Much less code to maintain, specially on heavy components such as forms.
• Much less documentation to write or maintain. We could use those resources to create new docs or improve the existing ones.
• Ideally, if we only define one default templating format, we could also optimize Symfony performance and configuration .

Cons:

• The tiny fraction of developers still using PHP templates will have to configure something or install something to be able to use PHP templates.