Would like to see more removal of deprecated functions and stuff. Cleaning.
We have Core and compatibility profile now. There is no reason to not remove/deprecate/clean old cruft form the core profile.

For people who find that it is more trouble than it's worth:
If it is too much work to replace obsolete functions and rebuild obsolete parts of algorithms. Then why the need to adapt the current program to a new OpenGL version? New features can also force rethinking of architecture.

I was a bit disappointed when I saw the OpenGL ES spec had a section of legacy features.
Because OpenGL ES 2.0 did not have backwards compatibility. Breaking it again would not have surprised many and would be expected.
Please do not do backwards compatibility again with OpenGL ES. Doing this is simply not necessary and allows for a lean specification without a lot of old cruft that makes it more work to build conforming drivers.