No I would not buy a subscription for a character builder for an open content game. I may be willing to buy a piece of software that does it, if that software does not suck, and it is a one time purchase.
I do not need a compendium for a game that is open content. I have the rules in full in the reference document. That works for a game like 4e with no open content, they can sell you a query tool that pulls from their SRDish document, and charge a sub for it.
I would be interested in some encounter building and treasure building tools, and would maybe even be willing to pay for them, if it was a one time purchase, they did not suck, and the price was right.
But no, I will not pay MMO prices for spreadsheet and DB query support for a tabletop game. Even if that game is one I like very much.
love,
malkav