I think dash needs to work on core competencies, i.e. providing a mixing service that will complete within a reasonable time frame. >48hrs for a darksend mix of 20 dash is impractical. Rather than spending allotted funds on conventions, why not incentivize a larger proportion of liquidity providers.
Something is wrong on your end if you can't mix 20 dash with 8 rounds in less than 2 hours.
Or else your settings are made to wait a long time between rounds.