Two very important options to add...

[Lewis]

1-
I would like it to have a test option, with an image with guide lines of the image box of the actual field of vision of the Commodore Amiga, that is, the real edge of vision marked with lines and in the center of the screen as you should see it. the edges, if due to some bad configuration you do not see those lines you are losing field of vision and you do not know it. (It happened to me, I realized because videos of x games on YouTube that I played showed a more complete image)

2-
Another issue would be to be able to move the list of configurations up and down within the list to access them more easily.

[Rock'n Roll]

In fact, this idea is very interesting. There are various screen settings under WinUAE/Display.
-TV (narrow)
-TV (standard)
-TV (wide)
-Overscan
-Overscan+
-Extreme
-Ultra extreme debug
-Ultra extreme debug (HV)
-Ultra extreme debug (C)

I would like to see another entry:
-DIW open border

This could look similar like Ultra Extreme Debug and display the border set with DIWSTRT/DIWSTOP partially transparently
(e.g. in blue) or with a small borderline around the screen.
The DDFSTRT/DDFSTOP marks on the left and right of the image would also be interesting (e.g. in red). However, I am more interested in the
exact time of the first and last pixel on the screen. (e.g. in green)

Since the settings can be changed at any time with the Copper or the CPU, something dynamic would probably also be useful.
Screen changes, screen splitting etc. or BPL DMA on/off should also be taken into account.
Maybe it is also another debugger feature? >vd (like visual display)
(Much or all of this information is already available in the DMA debugger and only needs to be visualized).