By "user tools" I mean the group of controls showing the current user's name (linking to their profile) and a logout link. On some pages these are at the top right; on most pages they're also at the bottom.
Why it matters
Visually-impaired users with ZoomText are particularly susceptible to changes like this. Once a user gets accustomed to a control or set of controls being in a certain location they will often return there. If the controls are not where they expect, it is often a laborious hunt to find them again.
User tools should be consistently placed on all pages, with no exceptions. Both at the top right and the bottom would be best.