A text range channel that is the text equivalent to the vox range channel just makes sense.
The room channel is fine and has some advantages over "range" - for example, it allows you to talk to people that are over the target while you are taking off from home-base and still out of the range for "range" talk. However, generally I feel that "range text" will be more useful for me to tune in the radio box than "room".
We can have both as HT says. The important bit is that the receiving side does not need to have the channel tunned in his radio box in order to see the text. If he dislike the channel, I suppose it will be possible to hide "range text" via the text window options, in the same way that I currently hide the "help" channel messages.