Compels. Compels are Compels, agenda-related or not.
At this point it feels like you're purposefully misunderstanding. There 2 separate points.
* Mechanically, a compel related to a specific agenda is rather like having another aspect. Not completely, but sort of. In fact, I'm not sure why (templates aside) an aspect related to your Sponsored Magic isn't a Must. I'd probably house rule that. Anyway, normally the GM compels you to act in keeping with your character normal behavior in an inconvenient way (using the aspects). Since arguably your High Concept (if nothing else) will reflect your sponsorship, the GM is free to compel you to do whatever your sponsor feels you should be doing.
* Narratively, it doesn't seem to make sense that "self-sponsored" magic has a debt mechanic. With Sponsored Magic, you're getting an extra boost from your sponsor. With "self-sponsored" magic, its just there because its part of Sponsored Magic but there's not really any justification for your boost.
Ritual + Channelling is kind of a bad deal compared to Sponsored Magic. Focused Practitioners in general are kind of weak compared to Wizards and Emissaries.
A Focused Practitioner doesn't generally have both (not that they can't). They also take significantly less refresh cost than Wizards. And Sponsored Magic has narrative drawbacks. Plus not being strictly balanced doesn't mean there's a hole. And "self-sponsored" magic doesn't really fix that problem anyway, since it all requires that you already have it... or at least that was my understanding. If I'm wrong then I have one more thing to add to my list of complaints about it.
Worldwalker is a bad Power for a Wizard to take, but Wizards who walk worlds want something like it.
It's not as versatile as using magic but its actually a really good power, especially for a Wizard who takes regular day trips to the Nevernever. It costs more refresh to get all of the bonuses as stunts, plus it doesn't cost you anything (other than time between entry/exit) to use.
First up, they can't use Discipline.
Sure they can. "Hey, GM. I'd like to take Breath Weapon [Fire] to represent my character's specialization in Pyromancy. Can I have it use Discipline instead?" There isn't anything special about the skills the Powers in the book use. They're just the most appropriate to the way the powers are described.
[/quote]
Second up, optimization 101 tells you not to pay full price for redundant abilities. You'll pretty much always be better off with Refinement, or with something unrelated like Toughness.
Aside from the fact that "optimization" is just a polite term for "minmaxing" (which is not a good reason to design things a particular way and as a GM would make me that much more likely to nix a custom Power/Stunt) Breath Weapon isn't redundant. Magic costs mental stress; Breath Weapon doesn't. That advantage is not trivial at all.
[/quote]
Third up, Breath Weapon is just kind of weak in general. Low damage and short range.
The RAW doesn't really specify, but I'm probably not going to let you throw fire two zones away with evocation, either. As far as damage, in a lot of ways many low-damage attacks are better than a single high damage attack. If my stress boxes are filled (which I can do in 4 hits of any strenght, technically) then I have no choice but to be taken out or fill a consequence regardless of the amount of stress I just took. But, yes, that was just an example. An appropriate specialization substitute would probably need to be a bit more powerful than that.