For a suggestion, remove the skills required to make chat distances longer, and just make the chat distances longer for everyone 
Half the time I think I’m replying to people who have 1000m chat whilst I have the basic 100m, or whatever the real numbers might be 
Perhaps on the compass stick a little dot on the player icon for people that can hear you? After all it must know the distances, otherwise it wouldn’t have different sized icons.
I understand the reason for scaled chat distance, but it does not feel good. Also, spending talent points on it feels like a waste. I’d rather see a standard chat distance and come up with some other talents to put in that tree instead.
I had a thought.
What if chat channels were just per region? You’d be able to talk with neighbors, and other city inhabitants, for the most part. But it still wouldn’t be world wide 
I would also prefer some other talents or skills. But if we were to improve shout range to be usable, I would guess it would be something like this.
Person who has upgraded shout range can talk for a much wider distance around him. People can listen to him, but can’t respond back. There will be an indicator that lets you know if you’re inside or outside the range to talk back to him the way we have now.
People who’ve upgraded have the option to receive private messages from people listening to his message, with the requirement of the players sending private messages being inside his area of range. That would mean, I could try to sell something. People that are in close proximity can use either “open world message” or “private message”. People that are outside the “open world message” can still send a “private message” as long as they’re inside the upgraded person’s range.
Or simply, the person who’s got an improved shout range, also gets an improved hearing along with it.
As for improvements in the explorer tree, I could see once stamina gets introduced, along with hopefully hunger and thirst, explorers decay on those much slower than normal folks, meaning they can explorer and wander for longer times.