thats like 2 million more than normal retirement, i'd rather grind up my alt to get more loompoints for my main^^
Considering that your alts are gen 1-5, whereas a main is gen 10-20, for most players, it's actually 1,4 times faster to level up on your main than on your alt for most players. So time for 8 mil with an alt <=> time for 12mil on your main. Also take into account that your alt plays 50% of the time below 30, when the main is already level 31+.
So, i'm totally against the idea of extra heirlooms for high level, or maybe, eventually one more for 33, two more for 34, etc... And nothing for 32, wich is... still low ? (one respect, and back to 31 anyway)