On OSI some skills have delays for success and failure and some skills do not have delays before you can use another skill (but delays if you use the same skill twice). It would be nice to have some options like that in skills.cfg

I know this scriptable, but perhaps it would be more efficient if the
core handled these things.

The only concern I would have over handing a scriptable option off to the core is when you do this youy usually take a hit in the flexibility department.

It don't see how it would make things less flexible. If you don't want to define the options for delay for failure, delay before using another skill, you don't have to. As of right now I'm probably going to have to disable all delays in the configuration files and handle them all myself, when it MAY be easier to do in the core.