I'm sorry, but I think that the lack of something as basic as a 'not equal to" comparison operator or even a simple 'isNull' check in the template code is not really keeping things simple. The fact that I have to write a whole new NotEquals() function inside the model in order to reproduce a very basic != comparison operator can hardly be called simplifying things. And I don't think preventing programmers from using a != in their if statements makes the template code any easier to read than standard PHP code.
Also, I'm not convinced that allowing PHP code inside the template means that the controller will become useless. It simply means that it is possible for the programmer to code in a way that makes the controller useless, but if the programmer wanted to stick with the MVC architecture, they could just as easily write clean MVC code using PHP in the template to control the view, and move any database/business/etc logic into the model/controller. I don't buy the argument that allowing PHP code inside the View will make the templates any less readable, PHP itself is a template language to begin with, why re-invent the wheel? IMHO a good tool is one that is flexible enough to allow you to get things done the way you want and also allows you to become more productive in the process - I don't think templating langauges offer either of these advantages.
Anyway, we could argue about this all day and not come to an agreement. I just want to be clear that I'm not bashing SilverStripe. I really do love this CMS and how easy-to-use it is for the non-technical end user, especially when compared to other CMS like Drupal, Joomla, and even WordPress. They clearly put a lot of thought into the WYSIWYG editor, making it extremely simple for users to create links, insert images, and re-arrange content - something that I've always found lacking in most other CMS systems. I also love how easy it is for a programmer to extend and customise the system. My only gripe is their decision to force the programmer into using an extremely limited, non-standard templating language, instead of simply allowing us to code PHP directly inside the templates.
Well.... actually another gripe I have is how the online documentation is structured - it's quite difficult to find the information you need at times, I also think the search engine for the documentation and forums could be improved. But I will leave this rant for another time ;-)
Otherwise, I am absolutely in love with this CMS and will continue to use it and recommend it to my friends/clients!