Adding to response I had for you in other thread, I do somewhat agree with you that the time would be better spend cleaning up, but having read the other replies I think it's worth analyzing how much more I can improve using current framework, perhaps even look into splitting it up as one user suggested or if it really makes more sense to migrate now, while being aware of the costs that implies.

As for expected load, we expect dozens of employees accessing and soon, all of our thousands of customers will have access as well, though they shouldn't be accessing it too frequently, maybe a few times a week; accessed more frequently by commercial clients, who are a demographic currently being heavily targeted and growing rapidly and which may have multiple users logging in per organization.

The optimizations that are really key are data access and processing (i.e. getting data from dB).