If I'm reading this right, every level over 30 you lose one of your heirlooms? or it gets a negative (MW becomes Sharp, etc ie: +3 becomes +2)
Because no. I don't like the idea of negative reinforcement to force you to retire or respec.
I really like the idea of a lvl 34 or 35 heirloom myself. Perhaps not connected to Lvl 31 heirlooms at all. Probably NO weapons. Just armor.
For example, an archer might retire at 35 for an aluminum mail shirt ( I know it didn't exist! Shut up! I could have called it Mithril!) that gives them additional protection without the weight penalty.
Primarily these items should only add hit points, not damage reducing armor. Armor would make some weapons that can hit now begin to glance on the Lvl 35 Looms and we don't want that.
This would allow people to live longer in fights, giving us more give and take than now. It wouldn't destroy current weapon balance and looms at all. But you might live through one more arrow, or pike poke in melee.