I think the AFK Bazaars cause a lot of the lag. I have 2 suggestions for a possible fix:

1. Make it so that Bazaars within the city only work in Area B.

or

2. Create a special Market Ward for all the AFK Bazaars.

or

2b. Move the retainers out of the Wards and into our bedrooms, conduct Market Searches/Purchases from the Inns...then use the Wards for Player-Bazaars.