Arguably anything, the space is substantial. Until you factor in the NCC. They control the land. Generally they would be favorable to parks, libraries, museums, subsidized housing. Not exactly big money maker for developers.
Furthermore, they have granted 6 acres for an arena/hotel, roughly 500 feet by 500 feet. For reference, 6 acres is almost exactly the size of the current building only. Thats not much room to do anything with. The NCC moves at a glacial pace, having sat on the land for the last 70 years with maybe 5-10% given up for development, although they did give the greenlight to near complete development 10 years ago, hard to say how that experience may sway them. After the last debacle, they claimed to be more interested in smaller more modular development rather than a huge vision package. But I hardly trust them to keep their vision from week to week.
Obviously the bidders have been eyeing this as a development opportunity, but you've already seen at least one high profile bid lost because of the uncertainty of any more additional land being made available and the general cold water the city poured on the idea of a Calgary type of deal. The league also claimed there was no issue staying in Kanata, although I think that was more to pressure the NCC and the city. But in any case, last years attendance numbers has most people thinking they are likely to be back in the 18000-19500 range in attendance soon, which makes a downtown arena a tough sell if there are not major concessions.
Ultimately the long and short of it is there is no guarantee of what will happen at this point, and that likely has the bidders a bit anxious. Anyone bidding with an eye of financing this via extra development and/or government sweeteners have probably taken a sober second look
