I'm very skeptical of how pleasant this park will actually be:
1. Unless the rail overpass is modified to accommodate active retail, you condemn that sidewalk to eternal dullness.
2. On the other side of the street, you have 4 lanes of fast traffic untempered by on-street parking. With the noise and the speed, it makes it very unpleasant to sit or walk by the road, which isn't good for active retail frontage which depends on people both sitting and walking.
3. Being between two large roads of traffic isn't super fun either and it isn't easily accessible (you can't easily jaywalk, so you have to walk however far to the next intersection). I think this space will end up being almost always empty and essentially useless.
What I would propose is a more efficient use of space to be as effective as possible in creating an active street:
A multiway boulevard would allow for fast traffic in the centre, parking, bikeable slip lanes AND a pleasant pedestrian experience sheltered from the noise of traffic. With the space saved, you could allow for much larger sidewalks and more space for a healthier canopy of trees. Let's not make this into another Viger.