It all begs the question of how open should it be. There are times when you need to be able to do just that, like adding memory or storage. Laptops are designed with the memory located behind one specific door on the underside (usually) to make upgrades simple. But given that the Surface loses much of its storage to Windows 8 to begin with, you'd think they would want to make it somewhat upgradeable.
Does it matter to you that the Surface Pro is virtually inaccessible and upgradable? Do you want to be able to replace and upgrade, like on a laptop, or would you prefer it stay sealed?