Dont break a leg trying to get them imo, if you get one…cool, but I wouldnt go out of my way or grind for them because outside of getting some easy trinkets/neck/rings on new toons they are pretty worthless now a days. I wouldnt dump gold on them or upgrades either anymore. ( you can use timewalking currency to get upgrade items iirc )
They used to give XP boosts, but they changed it to be much less useful. They arent even better than regular dungeon blues anymore iirc.
I think gear, in general, could be reworked. I like the idea of upgrading gear with a currency rather than constantly trying to find a specific piece. It’s one of the reasons I like the current catch-up system and remix.
The problem and point of this post as far as I can tell is the heirloom ilvls don’t grow at the same rate as the gear you’re getting per char level so the heirlooms are getting replaced periodically anyway (if you’re just replacing based on ilvl).