Utilize GL_KHR_debug to provide meaningful runtime optimization & use suggestions
It would be really cool to use the functionality of the OpenGL KHR_debug extension (also part of core OpenGL 4.3) to output hints/tips/debug information to lovers, with the ability to toggle it on and off.
This would only work well if the information made available can reliably be filtered into something useful to lovers (messages about the use of deprecated OpenGL functionality won't help anyone except for LÖVE developers, for example).
It should also be noted that KHR_debug is very new and only supported on modern nvidia drivers currently, as far as I know. ARB_debug_output also exists and is slightly more widely supported, but it's a subset of KHR_debug and requires an explicit debug OpenGL context to be created, which would have to be hacked into the LÖVE window creation code.