Two the biggest issues isn't those ones.
1. Plots are locked to a size.
2. Item limits are so low that most houses can not be fully utilized.

Solutions are:
1a. they can make all plots scale vs amount of gil you spend. Small 3mil, Medium 10mil, Large 30mil, Extra Large 60mil.(Allow you to start at the size you want by paying the starting fee for that size then upgrade at anytime to other ones for the gil difference on next one.)
1b. Make sizes Small, Medium, Large, Extra Large.
2. Make item limits for inside Small=500, Medium=800, Large=1200, Extra Large=1500. For outside Small=100, Medium=150, Large=200, Extra Large=250.