HN user
To widen this templating-aspect perspective to yet another extreme, here's more fuel for the fire.
http://www.webresourcesdepot.com/19-promising-php-template-e...
List of nineteen promising PHP template engines. Nineteen. And this isn't even tip of the iceberg. The templating diaspora can partly explain how MTV was received.
Noble and geeky effort, but I'm skeptical whether I'll use it (disclaimer: I did try smarty implementations before and had similar experiences.)
Think the dissenters' consensus is that this goes against grain of what's been organic WP development (not that it's all perfect, but, there is a massive contributing base.) This thing might become obsolete nightly or I could be entirely wrong and it'll get adapted whenever WP guys wrangle major internal design changes at some point.
I'll skip over all that and just address specifics that make me feel uneasy.
As they stated in their writeup, one problem is that function exports have to be hard-coded. Not to say they won't fix this (switch it to smarty3-like model or control what gets installed), but that means they've interfered with the admin process of installing plugins that need minor template alterations or otherwise meet unspecified limits; ex: wp-paginate. That means that the core MTV team is still involved with the end user, and the template designer.
Secondly, sure, WP templating hasn't changed all that much lately - but historically it has changed drastically between major releases. This MTV implementation forces Trib. guys to spend time keeping up with updates and changes that will come out of nowhere. I'm not sure if MTV breaks WP's template hierarchy, or its template inheritance features, but those I rely heavily on.