Clients requesting channels for themselves shouldn't have to jump through hoops to do so, and if you request a channel for a particular other application you'd better be sure it can deal with it.
Please mention in the rationale that this also allows a client to become the handler for a channel that it requests, without being forced to be a candidate to handle *every* outgoing channel of that type.
The semantic change looks good to me, but I don't want this in the spec until it's true in our reference implementation, so I'm setting the corresponding MC bug as a blocker.
I'd be willing to have this in 0.19.0. Since we only have one practical implementation of a ChannelDispatcher, and this functionality only works in the latest version of it, it may be worth explicitly noting "In telepathy-mission-control, this works in version 5.3.2 or later."
I've hijacked this branch to get it into 0.19.0. See:
Fixed in git, will be in 0.19.0