Currently it's difficult to tell how old a torch is.
Took a look & don't believe this can be changed with a simple resource-pack.
I'd be happy to provide textures for torch burn states if necessary!

We use the issue tracker exclusively for bug reports, not suggestions or support requests. This post would be more suitable for our discord's suggestions channel.

That aside, no it is not changeable via a resource pack unless said resource pack can read block entity NBT (which I don't believe it can).