In high school Jackson played on both the OL and DL as well as special teams. In addition he was on the track/field and basketball teams. He was a 5 star recruit and the top rated prospect from Arizona.
He played in every game at USC. For his freshman year he was a reserve player. For his sophomore and junior season he was the staring left tackle. He was first team all PAC 12 for his junior year. His grandfather was an OL guy for USC too and went on to play for the Packers.
IMHO he as already done enough to prove he doesn't suck. I suspect, given his young age (20), he will need a couple/few years to hit his peak. I too think he will become a good player for a long time.
When you saw guys like Isaiah Wilson and Ezra Cleveland go as early as they did I don't think you can fault the team for drafting Jackson and Hunt where they did. At the worst Hunt will be a great guard. If Ruiz was an okay pick in the 1st then Hunt was a steal.
Given a couple of years I think Jackson (LT), Kindley (RG), and Hunt (RT) will be a formidable group.