Instant feedback ...

You have major problems making this work. If everyone acts in good faith then it would be brilliant, but it needs to be resilient against bad actors, and that's hard. Really hard.

Suppose I get someone to do a job, and then I don't pay? Suppose I claim the job was badly done. Or suppose the job was badly done? How will you resolve the dispute?

You say the ranking system will sort that - suppose I maliciously give bad rankings to other people in my area who are competing with me for jobs.

Having seen that some people really will set fire to the Earth just to watch it burn, I'm not sure I'd ever want to get involved at all.