Thinking more on the ley line poisoning idea (if you choose to go that way): I could see it being an interesting focus for a campaign. While the "stop the ley line from being tainted/cleanse the ley line" might seem like a one trick pony that would get tired, I think not.

Ley lines all represent different flavors of energy. Perhaps tainting Ley Line A requires a different method than tainting Ley Line B. Ley Line A might be a pure vein of earth magic, and tainting it might involve toxic wastes of some sort, and Ley Line B might be a river of protective magic. Tainting Ley Line B might involve brutalizing something that's always been protected or that should be protected. Similarly cleansing these lines would require something "in flavor".

In this way the players might have a basic idea of what they need to do "preventative or damage control", but have to figure out how to do those things differently at each location.

I'm thinking of making a true shapeshifter who gained its powers because it was stripped of it's "true name" (Self Identity?) by a wizard's death curse.

It builds a new form by forming a mental framework for the new "person" it is going to become. It will have limitations along the line of "if you can recognize it from a previous identity, naming it with intent (invoke of high compel) can force it into the identity you knew it by."

I think one of the bigger problems is going to be people wanting custom stuff. In most games this isn't too much of a problem, but DFRPG encourages custom stunts and powers. You should have a fairly level head on your mods, mechanics wise, so they can spot any issues that might arise from such things fairly easily.

I have to pop in here to warn you that a focused crafter is really scary powerful, more so than the average wizard. If balance is a concern in your game, you should be concerned.

I'm a little leery of anything Monte Cook has had a hand in.

+156?

Remember I'm intending to limit it to a single +12 bonus to the leader, not everybody. It was edited in after you pointed out that the wording was for each member not just the leader a few posts back.

I wasn't intending it to be a bonus for each member, but a bonus for the Ritual Leader. I suppose my Shadowrun gaming is getting in the way (there is a very clear distinction between participants and the person running the ritual in that system).

So yeah, the person "running the show" is the only one to get the bonus.

I dont see the +1 per family member participating in a ritual as overpowered in narrow circumstances (having a full contingent of family helpers for a ritual). Consider that the cap is 13 total, so 12 others helping (canonical, according to Dresden in Blood Rites), with 12 others helping your ritual is going to be so powerful that the +12 is going to be small potatoes in the overall picture.

Though yeah, underpowered in narrow circumstances for sure, I'll think on it some more.