Would it be possible to "upgrade" the combinator into the LTN Trainstops?

It just feels bothersome to have already 2 combinators in the trainstop and then still require a 3rd one that needs to be additionally placed and connected to it just to be able to configure the stops.

This should actually be functionally integrated into the LTNs themself.

That would be something that needs to be requested of the LTN Mod. Given that it is designed to be controlled dynamically by signals that could potentially be quite remote, I assume that the request wouldn't be implemented.