A toggle to remove the tail from the bubbles.

[jjohanss]

I'm pretty sure the css also had an option for showing the tail in the bubble to make it a speech bubble. Not a usability thing but something that could propably be implemented quite easily? A style thing.

[kethinov]

This one might be a bit tricky but I'll look into it.

[pestophagous]

on Yosemite, the png files that control the shape of the bubbles are here:

ls /System/Library/PrivateFrameworks/SocialUI.framework/Versions/A/Frameworks/IMRenderingFoundation.framework/Resources/bubble*png

As a quick proof-of-concept to verify that these files can be tweaked, i used ImageMagick to run the following:

for i in bubble*png; do sudo convert $i -fuzz 80%  -transparent white  $i; done

That will turn the bubbles into rectangles, as shown in this attachment:

the rectangular look is fairly boring, but at least this hints at a path to more subtle tweaks of the bubbles.

sidenote: i discovered where the bubble png files live by launching this in a terminal window:

sudo dtrace -n 'syscall::open*:entry { printf("%s %s","testing",copyinstr(arg0)); }'

then open Messages.app and watch the running dtrace output to see which files are being accessed.