That is being looked at quite extensively. There are a number of opportunities with that link, and several obstacles that will have to be addressed. Its doable, but ultimately it will come down to funding to make it happen.
On that note, NCTCOG selected a project for funding that would effectively create a dedicated bike/ped connection from the Houston Street bike lanes, through the lower McKinney Ave. area and connect to KWP along Harwood and other streets. Funding is still contingent on Regional Transportation Council approval, and that is expected in the coming month or so.
This does not create a connection to the Katy Trail along the northern end of Harwood, but perhaps this project can be considered 'Phase I'.