Wow, this thread was plucked out of the depths.
As has been said, Section 37 agreements are very common and their is no "under-the-table" activities. It is perfectly legal and transparent.
Section 37 of the Planning Act permits the City to authorize increases in permitted height and/or density through the zoning bylaw in return for community benefits, provided that there are related Official Plan policies in place. If you want to know more about the protocol, check the City's Website or give your councilor a call.
The owners/residents of ROCP do not pay for this. Nor do the taxpayers, per se. The developer agrees to pay a sum to the city (which the City earmarks for a specific, pre-arranged purpose) that will go towards community benefit. This includes, but is not limited to, renovations of parks, libraries, street appearance, lighting, community centres, etc. The funds usually go towards a community site that is close in proximity to the developer's site but this is not always the case. The important thing to know is that the city still retains ownership of these properties/amenities despite the developer's Section 37 contribution.
The public art component of an application is separate from Section 37 and so are agreements for the developer to pay for new traffic lights, a share of new roads and other aspects of infrastructure that are usually co-financed by the developer but then turned over to the city.
As for this park itself, refer to the Aura at College Park thread for more info on the renovation of the park. The developer has incorporated a lot of its renovation exercise into rebuilding Hayter Street (as a pedestrian mall) and providing a proper entry-point to the park from Yonge. A huge glass atrium is to front the park and the public art will look out onto the park. What is unknown is the specific changes the City plans to make to the park with the Section 37 funds. Perhaps the City hasn't decided and will wait until after Aura is built to put the earmarked funds towards area improvements.
Also, there was some confusion earlier. The City, not the developer, pays for and maintains the park. For example, it is the City's budget that supports the rink maintenance and park grooming. That won't change. However, given the park's grungy underbelly, it is not known as the safest place in town. Given that I live overtop of it, I can tell you from experience that beatings, drug abuse and other unfriendly activities take place here on a nightly basis. For that, the property managers of the surrounding buildings, especially College Park and 777 Bay, provide security personnel that patrol the park. The Police Station is just across the street and it is not uncommon for horseback cops to patrol the park as well.
Other info on the park: the new town homes are hideous.