Regarding deprecated functions

Are the deprecated function feature going to be kept in for the long term?

I still have some use for them because they can be called by name so it makes it very useful for running commands from text and I want to use them as functions you can call from JSON scripts, dialogues are slow paced so I don't mind the performance impact.

I'm wondering if this will be a problem in the extreme long term, as this is a project that I'll have to be working on for atleast a few years

I suppose old functions will be supported for a very long time, for compatibility reasons.

Also, you can call new functions by string name using function maps.

When features are deprecated it means they are on track for removal. So you should stop using deprecated features as soon as possible and not use them for any new purposes.