Residents around the arena district didn't want it because of constant traffic (grandview, italian village, victorian village, harrison west and actual arena district) so Franklin County had a public vote for it, and the public voted to move it to the west side.
The site in the arena district was IMO awful and the 670-neil exit would need a major overhaul, but it's landlocked on 3 sides. It needed more planning than what they were willing to give it