The increased stats for players were removed and permanent 100% HP/SP/LP extender and permanent 50% damage/defense charms are now available at the guild item merchant for purchase. These were originally the stats that were being enhanced, now just handled by the premium items instead.
All chest pieces now have 66% crit rate and 15% phys/mag damage. Again, to make up for the lost additional stats that were added previously (These are what costume stats would've given you in the original game)
Special chestpieces (blues/greens) throw in +30 to all stats, which is what the best mini pet item would've given you in the original game.