Look at current downtown park usage, and it is easy for any reasonable person to see that there is very little demand for the park space that exists now.
One option might be to develop the 10th & Main site in such a way where there are some retail spaces at the back edge of the parcel with a outdoor public plaza in front with tables, where patrons can sit outside and eat. Make the public plaza part of the retail property for them to manage, and keep the responsibility out of the parks department. If the parcel was combined with the 1034 Main property, a tower could eventually be placed atop that parking garage and have the entrance to the building be on part of the transit parcel.
Keep the retail building at one or two stories so as to not block the windows of the apartment building on the west side.