I listened to his speech from the 2012 Texas Dem Convention and he's a decent speaker. Certainly he was chosen to connect the the Latino/hispanic communities, but he is seen as a rising star in Texas.
I would think that associating yourself with the national Democratic party by being their keynote speaker would pretty quickly quash any rising star in Texas.
...and you would be right, for the time being. I'm guessing that the Democrats are betting on demographic trends in Texas. As of the 2010 census, whites were 45% of the population where as Hispanics were 37%. This trend is the only hope Democrats have for a statewide win going forward and that's probably why they are propping up Castro, who is the only remotely strong candidate on the TXDP bench.
