Yeah, I don't think the highline is a good comparison at all. I just named it because it's kind of the same idea of re-purposing old infrastructure.
As a cyclist myself and somebody that uses this type of infrastructure in cities everywhere, it's about creating multiple and contrasting river crossings. If you have the new bridge, the old bridge, the HOA bridge etc, you could build one hell of a parks system on both sides of the river and all of those bridges collectively would create a bigger destination than just going back and forth on one bridge. You have a full blown downtown recreational destination.
This is why I'm not so sure it has to be this fancy linear park thing. I was thinking something that cost a bit more than tearing it down. I mean something like the Little Island also in NYC is quite amazing. Not sure if you have been, but it's a park on what used to be an old pier. It's now a top attraction in all of Manhattan. I have been a few times. It really is neat, but it too is tied to bike trails the Highline etc.
Obviously KCMO is not going to do something like the Little Island and the city may not even be able to pull off a full blown park and keep it going with events etc. KCMO will need to figure out how to properly maintain stuff like that.
But KC should really think about doing something like what they have in Richmond VA and man other cities. Multiple bridges crossing the rivers connecting parks and different districts together. They are massively popular. Here are some pics of the Richmond Bridges: