To 'educate yourself', try going to the GCRTA site to see general information on the Waterfront line extension.
By the way, just beacuse you haven't 'heard or seen any concrete plans' does not mean that it is 'just all specualtion'.
Anyone heard of the Waterfront Rapid Line being looped around and connected through Downtown or it heading off to Bratenahl? This issue has died, it seems.