I think some license is better than none and that Tx is more stringent than most of the other states that require licensing. The problem with hands-on training with the current system is that there are simply too many possible scenarios to really teach adequately. Anytime I've brought on a new guy without experience, it's taken a minimum of 3 months before I felt they were competent enough to head out on their own and they would still run into things that they'd need help frequently on for at least another year. I'd love to see an apprenticeship and practical applications testing like the plumbers have because it would insure that the guys with licenses could actually do the work and make the barrier to entry a little higher.
All that said however, without some real enforcement from the state and local authorities of the licensing laws already on the books, additional requirements are a waste of time. Easily 1/2 the guys working on irrigation systems in Houston don't carry the proper license now and more stringent licensing won't do anything to improve that. I really don't understand why TCEQ doesn't do a better job with this, an enforcement guy could easily collect more than enough in fines to justify their position just by hopping in the truck and driving around town for a week.