This is something that I always find myself using, either to adjust the time or the size of the animation. Maybe it would be good to have a easy access button for this, it could be besides the Render and Preview settings buttons.
How about using submenu with accelerated keys?
Yes, I know there’s F8 hotkey shortcut.
But a button on Canvas window is easier to find (for new users) and easier to remember (for experienced users). IMO, it seems like a positive thing to include in UI, and a “Canvas Settings” button would fit nicely besides the “Render Settings” and “Preview Settings” buttons.
Then a customizable toolbar system would be a proper solution for it (So that users can the UI for their own workflow). I will fill a feature req in our issue system.