MongoDB 3.2 has improved its geospatial performance with several key changes, including the avoidance of repeated index scans by maintaining a union of visited cells and taking the difference between coverings to minimize unnecessary document fetches. Additionally, increasing the finest indexed level constraint for points allows for more accurate estimated distances without significantly increasing the number of index keys generated. Other improvements include changing the format of index keys from strings to numbers to reduce size, and setting a finer query finest level to improve covering selectivity, resulting in significant performance gains for queries over dense datasets and small areas.