That's an interesting idea. It would be much better than relying totally on a trusted third-party to handle it, since they can't steal your money in this case.

Many of the script ops (like OP_XOR and OP_MUL) were disabled when it was found that some of the arithmetic ones could be exploited to crash all Bitcoin nodes. Those need to have their security closely examined before they are enabled again.

I'm also strongly in favor of removing IsStandard restrictions, especially when relaying transactions. I modified my node to accept non-standard transactions, though I don't mine, so it doesn't matter much.