Along with power play issues and the recurring mental lapses, the overall play style would be a primary reason to change coaches. It would require significant personnel changes, too. If you wanted to mimic Vegas or the early 2010 Cup teams, you'd need to get bigger in multiple areas.
I think Tampa is still the best way for the Pens to structure their team - it rewards high skill, which the organization has always preferred, and maintains a speed element. But there is a grittiness and physicality to Tampa's game in its prime that rewarded players who relentlessly pursued the puck. You have players big enough and strong enough to win board battles, win battles around the net.