Winetricks should probably force YAD / Zenity for all users due to the lack of consistency presented when using kdialog.
IIRC Yad is not relevant for Winetricks; it's only relevant for Protontricks. Zenity should be the one forced on everyone because Kdialog is really lacking in terms of visual "correctness".
And then the "--gui" option removed.
See Matoking/protontricks#429 for more discussion.