Confluence Park is indeed slated for a rebuild in the next couple of years.
there are lots of info and pics here:
Here is a mockup:
This deisgn includes replacing the diversion dam structure on the river left side with a series of wave features that would only run at higher water, and improving and lengthening the low flow channel on the right.
There are many other projects on the drawing board for the urban river. Probably the most significant from a boaters perspective is the replacement of the large drop at Florida ave with a series of drop structures. For an overview of all the planning that has taken place check out these "vision Plans" The Greenway Foundation :: RVIP-South Platte Master Plan
Also just for reference, you can cartwheel in Confluence year round. even below 100cfs. You have to know how to work an eddy line and have a quick roll, but almost all of the drops give up a few different moves. Loops not so much...enjoy