I'm just learning about joinmarket, so please forgive if this is a dumb suggestion, already implemented, or whatever.
I was just wondering if the weaknesses quoted below could not be overcome by something like:
1) takers provide multiple receive addresses. say a random number between 5 and 20.
2) total output payment is divided up randomly and sent to these addresses.
3) each payment is time delayed by a random amount between 60 seconds and max secs, where the taker can define max secs.
It's good to think about possible attacks so we can look out for them.
Privacy is a multi-faceted idea. I don't think CoinJoin or JoinMarket entirely solve the problem. A single CoinJoin does nothing to help with time-based or amount-based privacy invading, because the deals happen apparently instantly, and if you send in an amount of bitcoin you'll get back out that amount minus fees.