The main thing that keeps an MMORPG going is the "meet new friends and play with them" part. If you can't contact your friends conveniently, you don't only lose a main aspect of the game but also make it impossible to organise RP OOC.
In the beginning it was discussed to reduce /tell just as you said, but it was decided to not go that way. You can skim the forums about it. The relevant threads should be somewhere on the first pages of the wishlist board.
For /guild it's similar but for most guilds probably less about organising RP than about keeping in touch with friends.
If you like, you can try to turn off the guildchat for your guild by removing the privileges of the members and see what happens
While I agree that people should be able to contact GMs conveniently, using /help for this is a bad idea.
Everyone can see the what's being said in the /help tab by simply turning on /advisormode. This way regular players can give advices to other players and with GMs watching the channel the bad advices should be minimised.
However, noone guarantees that GMs watch the channel continuously and the more players join the game the less we will try to keep a permanent eye on it. Drawing samples and using a yet-to-be-implemented means to prevent players from activating /advisormode should ensure the high quality of the advices given.
With this it'd be gambling to try and reach a GM over this channel. The means of choice to reach a GM is /petition.
I was and still am for implementing a command /gmcall with which players could call for GMs when they need immediate help as /petition may take a while till someone gets back to you. This would make any other suggestion redundant on how to reach a GM in urgent situations.
Getting back on topic:
I was pondering about ranges in the open channel communication (/say, /shout). How would it be to substitute all these distinct commands by a slider on the left side of the /main channel which could be used to directly set the distance of what you say?
In direct command syntax this would look like /say [range] [message]. Normally the slider would remain in the position you set so you could have convos in lowered voice that only the people next to you could hear without learning and switching to new commands. Especially in mass-events I felt this needed and (inconveniently) emulated over /group.
As an additional idea one could set the color for minimum range and maximum range (as you can for /say and /shout already) but now the engine would mix the colors automatically according to the "volume" (range) of what's said.
Another additional idea building on the above would be to have a skill or spell that treats the outgoing messages of all people around as if they were said "louder" than they were with the effect that you can eavesdrop on whispering from farther away.
Opposing to that, one could think of a "dampening area"- spell that reduces the range of all messages - which (if strong enough) could also render spell casting with vocal elements useless.
