IMO, if thats a 2.5 year old deer, he has great potential. A deer will not hit its antler potential until he is atleast 4.5 years old with good nutrition. Let him go another year if your after bigger and you might be shocked at what he grows into.

Unless you have a high fenced ranch and know the genetics of every single animal in that fence, it is IMPOSSIBLE to change the genetics of the herd.