We are west of Sherman / Dennison and experiencing growing pains just from the build up of US75.
The growth is going to come regardless of whether or not this road (and others) are built. The TTC corridor through your area will likely simply replace much of the planned Collin County Connector, so if the TTC isn't built that road will be (which would likely be a tollway built by the N. Texas Tollway Authority.)
Like it or not, it is going to be varying degrees of development all the way to Lake Texoma within the next 30 years. DFW added 168,000 new residents last year, and the fastest area of growth is Collin County and northward. Probably the only way to stop development is to either buy up the land for parkland/preserves or adopt multi-acre zoning (to at least keep a somewhat rural character.)
I know we need roads badly--but I hate the planned corridor. In my mind, it would cut the state in half, and would be a real problem for the farmers as well as small business owners who are established now on I-35.
I would prefer that they widen some of the "back roads" that now exist. If doing that would relieve some of the congestion on 35, that should take care of the problem.
We travel 35 very often between Austin and Dallas. We plan it so we are not in rush hour. Of course, being retired folks, we have the luxury of doing that, and I realize that not everyone can.
Another idea that I have thought about is building a four lane road, roughly following 35 and make all 18 wheelers use that road.