I prefer seven. It's better to have a couple that don't carry their weight-- as long as it's not too many-- than to not have enough to really describe your character.

1. Weapon ratings on Attack evocations cost 2 shifts for every +1. +0 Weapon rating costs 1 shift. Evocation spray attacks divide by shifts rather than by Weapon rating and Weapon: 0 evocations are allowed. In my experience, evocation attacks are way too powerful; admittedly, the games I'm running are very high-powered.

2. I don't know if this is a house rule or not, but you get an extra stress box for every odd rank in a skill. An actual house rule is that you get an extra mild consequence at +4, and (theoretically) an extra moderate at +8. (Current PC skill cap is +6, but they're facing opponents with +7 skills.)

The "limited edition" backer benefits are either the Consultation-- which requires considerable effort-- or the ones with the dice.

As for damaging the company, with the exception of the core books I suspect that the price of producing each of the stretch goals was built into the stretch goals themselves, so at worst they're simply making the vast majority of their money up front. It's a sound business model-- you only produce what the customers want, and you make all of your money up front, so everything you sell after the funding campaign is over is long tail profit.

There's two different ways to attack a lot of enemies at once:

You can make a Zone attack, which costs extra shifts of Power but hits everything in the Zone with your full Power and full Control. A Weapon 4 spell hitting everything in the Zone costs 6 shifts of Power. This is good when your Conviction is higher than your Discipline and you aren't in the Zone with your targets. This is the Dresden "everything was on fire and it wasn't my fault" approach.

You can also make a Spray attack, which does not cost extra shifts of Power, but requires you to split the results of your targeting roll among different targets. A Weapon 4 spell would only cost 4 shifts of power, but you would be dividing the results of your targeting roll-- your Discipline-- among the various targets. This is good when your Discipline is higher than your Conviction or when you are in the Zone with your targets. This is the Luccio "laser beams of death" approach.

Like other posters have pointed out, it's the difference between using a machine gun and using a grenade for attacking multiple targets at once.

I'm currently using a blend of FATE Core and DFRPG to run two games-- a Spelljammer game and a game set between the "real world" and a grim and gritty envisioning of the Mario Bros universe.

Main change I've made to the magic system is that I've added more "elements"-- there are multiple characters with the Shadow element and one with the Wood element. I'm thinking about replacing the standard element system with something more akin to Legend of the Five Rings, with Earth, Fire, Metal, Water, and Wood and giving each of them "spiritual" qualities that replace the Spirit element. At least for the shroompunk game. DFRPG's standard magic system is actually a really good substitute for D&D magic.