That rule increases the house edge from 2.19% to 7.97% and the Element of Risk from 0.53% to 1.90%. This is because the dealer won't qualify more often and it will be harder to win on the Blind bet, which requires a straight or better.
For more details of my analysis, please see my new page on the Auckland variant of Ultimate Texas Hold 'Em.
For discussion about this question, please see the thread ULTIMATE IN NEW ZEALAND in my forum at Wizard of Vegas.