There's a couple other useful free online tools for DS, both for character creation and Director aid/prep:

Forge Steel: andyaiken.github.io/forgesteel/

Stawl stawl.app

Draw Steel is awesome for heroic fantasy, verging on fantasy superheros.

For class prototypes, the designers recommend a triggered action, a signature, a 3-cost, a 5-cost and a class feature. With 5 things is already possible to test something.

What some people want is to not have to choose between one or the other; and some of them are not happy doing a bit of both either, they want to do both well. That's almost guaranteed to break balance, specially in games with multiclassing.