In the current UI (1.0.0.92) there are two groups of three buttons each at the top of the screen. As my most frequently used button is the one for turn summary and this one is pretty small, I request moving this one and the statistics button to the group of the large buttons. The game settings / pause menu should stay a small one as it is not important for playing.
My preferred order of the large buttons is:
Turn summary > Planets > Fleets > Statistics > Quests
Unite gamplay buttons at the top of the screen
Unite gamplay buttons at the top of the screen
Master Of Orion 2 = Great
Master Of Orion 3 = Trash
Horizon = The real Master Of Orion 3
Master Of Orion 3 = Trash
Horizon = The real Master Of Orion 3