I would like to propose a UI change for the Input Source indicator of gnome-shell.

Currently (as of 3.10 - I believe same is true for coming 3.12)
the input Indicator menu first lists Input Sources, then
IME menu items (for ibus IMEs), and finally keyboard layout
and settings items.

It would be better for IME users (and consistent with the ibus applet
still used for our desktops) to list the IME menu items (if present)
before the list of Input Sources, and I believe this is also
more consistent UI: the indicator icon shows the current Input
Source and so having the IME menu right below that is more natural.
This change would have no effect on xkb layout Input Sources
since they do not have an menu items.

To summarize here is a sketch of the menu before and after.

Before:

[あ]
/-----------------\
|* ja IME      あ |
|  US layout   en |
|  other IME      |
|------------------
|  Input mode  >  |
|  Config         |
|------------------
|  Keyboard layout|
|  Region/Lang conf
\-----------------/

After:

[あ]
/-----------------\
|  Input mode  >  |
|  Config         |
|------------------
|* ja IME      あ |
|  US layout   en |
|  other IME      |
|------------------
|  Keyboard layout|
|  Region/Lang conf
\-----------------/

(In most cases it would also be better to
open the "Input mode" submenu by default
but that might be a limitation of gnome-shell
and ibus and probably needs a separate report anyway.)