I don’t think that adding two extra uses of channel per level is necessary. It won’t take many levels before the extra uses are absolutely meaningless. This would change if there were ways to burn through additional uses of channel. For example, bumping the dice from d6 to d8 could require an extra channel. Using a channel power or domain power (such as dealing fire damage) could require an extra channel. Just examples.
Hmmm. So the extra channels was to match the barbarian rage. My idea is that channeling is the primary combat technique, with spells an occasional thing, so I wanted to make sure they didn't run out, even if they used some for out of combat healing + utility. Note that they can still use quick channel to burn through channels at a fast rate, although the quick channel doesn't get the channel powers for balance reasons. Still, I like the idea of using channel powers requiring extra uses.
I don’t like the way you are dealing with spells known. Depending on which domains are chosen, it is possible that a 1st level character knows literally one spell. I love that domains are to play a larger part in spell casting, but this is too restricting. At this moment, I don’t know of a solution that is a compromise between your spells known and standard spells known. While I’m on the subject, three domains at 1st level is probably too much too soon. I would recommend two, and then gain additional domains at higher levels until all are known.
I don't know of any three domains that all have the same spell known, so while that's possible, it seems unlikely. Maybe say that if two of your domains have the same spell, you can take any other cleric/oracle spell? That would guarantee three spells known per spell level. And of course they can also take extra arcana. Also, the character's main role is supposed to be channeling, with spells a backup.
Ideally what I would do is create a small list, like 2-3 per level, of appropriate spells for each domain, and then allow the channeler to choose spells from all of those domains. That would be a ton of work though, so I'm going to pass. :-)
Hmmm, on domains most of the first level powers are fairly redundant, some sort of minimal standard action attack. Having three of those domains just gives more options, not much more power. Let me ask you, or the community are there three domains that having all of the powers plus the enhanced channeling would make you at first level better than a first level cleric with two of those domains, lesser channeling, but with the full spell list known and better HP and proficiencies?
The balance point I'm going for is comparing with cleric or oracle.