I don’t agree with this one. The button is located on the left and can be conveniently operated while changing the exposure with the other (right) hand. The right side already has many buttons, inc. the exposure adjustment which you’re supposed to play with when testing the depth of field.

* Eyecup loosely attached to the viewfinder

This is a little nagging, and I personnally don’t consider it a problem. It is comfortable and easily removable as it is. Might feel cheap, but does a good job.

* Limited access to the focusing screen (to clean it)

True, although I never had to do it.

My contribution to the list would be this one: the dioptric adjustment range on the eyepiece is too limited. As many people in their 40s I need a slight correction. By slight, I mean I’m perfectly able to read a standard newspaper without glasses. However, I do feel that the proposed adjustment range is not wide enough. Especially the focus indicators are slightly fuzzy for me, but are supposed to be perfectly sharp. And I don’t feel comfortable when shooting with eyeglasses.

This is a real problem for me and may not be Canon-specific. Any suggestion from experienced glasses wearers would be welcome.