To develop the lot with a downward slope it would be natural to think that some amount of fill would have to be brought in. Depending on the stability of the existing grade and sub grade there may be additional work involved to remove the top soil and compact the sub grade before the fill is imported.
With 1.5 acres it could be that the existing fill material would be adequate if the top soil was pushed off and the sub grade was regraded to a new consistent elevation with a slight slope at the front of the lot. If an excess of top soil is available when the lot work is finished you should be able to sell the top soil or trade it for fill material..
Whether you could do this would be best determined by a site engineering firm that would run a topo drawing with existing and proposed elevations. The topo can then be bid by excavating companies and let you know what the development will cost. (Since the soil bearing capacity under the building is different than under roads and parking areas and landscaped areas. Unless you know building sizes, drive and parking area locations, etc it will be impossible to determine where the greater capacity is required and the areas will have to be over sized.)
You will have the costs of the engineering, the earth work and fill work and the utility installation (water sewer electric) that would need to be paid. In addition you would have to obtain any / all necessary permits, authorizations and approvals.
All of this would be time consuming and you may be developing the lot in a manner that would not be suitable for the eventual user. It is possible that the ultimate user with his engineer would be able to develop the lot to exactly what they want and for less money than it would cost you.
The best way to make the most money would put it on the market "as is" and let a developer handle the time consuming and expensive work. You can make money on your land but you may cost yourself money if you are not as efficient at the developing game as they are.