Hmm..I don't see any commuters detouring off the pathway to a short stretch of bike lanes with a few traffic lights...it's a bit of headscratcher to include that in the rationale:
Too many cyclists going too fast sounds like a great problem to have. There should be plenty of space to twin a wheeling-only lane from Deerfoot to Carburn Ped Bridge. At which point you could encourage commuters to cross west of the river where the pathway is flatter, more suited to higher speeds, and has fewer pedestrians (aside from the off-leash areas, which are thankfully fenced with only a few specific ped intersections).
Could it be as simple as a 25 or 30kph speed limit on the west side and a 15kph limit through the rest of Carburn Park?