...I think If you craft a top tier item then it should scale with character level. That is, if I make the level 24 robes for my wiz, he should be able to wear them from level 4 on and every 4 levels they should automatically scale themselves up to the next tier.
Before, since the level 20 version was the only thing worth having, there was only 1 version worth making anyway, so there really wasn't any issue.
Level 4 robes -> extremely lame, can easily get better gear for few plat off the AH.
Level 8 robes -> extremely lame, can easily get better gear for few plat off the AH.
Level 12 robes -> extremely meh, can easily craft greater necro focus ML 9, pirate hat with superior false life ML 9.
level 16 robes -> meh, by level 16 you'd obviously want greater focus so the +1 focus is worthless, GFL is nice but easy to get elsewhere, the rest is easy to get for a few plat off the AH.
level 20 robes -> now we're talking! SFL (better than the easy to come by GFL), Superior lore (best lore available), greater focus (same focus you can craft ML 9, but frees up whatever slot you had that in), and some meh thrown on top.
It was a no brainer, level 20 or bust. There was simply no reason to craft anything else. However, now that they've added:
level 24 robes -> everything the level 20 has plus good nullification and Major focus
You're obviously going to want the level 24 robes when you get to 24, but the level 20 robes would be great from 20-24. However, is grinding out another 5000 motes 2 vamp, and a lich worth it to make a level 20 item that will become absolutely worthless once you hit 24? (Worthless because you have the level 24 version.) It's not like you can pass it on to another toon like cove items.
So considering how grindy mabar is and the fact that the items are BTC, it just seems obvious to me that they should scale with character level to the max tier they were crafted. Instead of auto scaling, you could have an NPC in Deleras graveyard that could manually set the tier of the items for a small price, if that's what you're in to.