I dont get the problem with the base item cost? You already need a new base item crafted with the new reagent for the rank 7 anyway
The easy solution here would be to make them all craftable on either a ring, cloak or neck slot, as well as their respective armour slots
Um there's 5 tier set pieces, you can easily have 1 out of the 5 slots for the legendary since you only need 4 pieces for the tier set
This is not really that big of a problem. You only need tier in 4 out of 5 slots and if you get a tier in one of your legendary slots just disenchant the legendary for mats and craft it on a different slot, ez
A simpler answer, which would have a hit on crafters like myself, is to reduce the mats cost and reduce the requirement to craft 15 of the previous level to something more achievable like 5. We only have 2 or 3 legendary crafters on our realm who regularly post items, (I don't regularly post yet, other than trying to sell off the lower pieces, as I mainly levelled to help the guild out & am still levelling some slots). Between them they've brought their price point down to around 50K* for a T6 piece, 60K for some of the more expensive leather ones. Some are lower than current crafting price. Callings generate 2K each, 14K per week, so 20K would be a more sensible price for the crafting cost.Lower entry/crafting costs mean more competition, which will lower prices.
Making neck, rings or cape available for legendaries conflicting with 2 tier slots would be the best way to resolve these issues.When people upgrade their legendary to Rank 7, they can disassemble their old legendary, and use the materials to switch the slot.
Make all slots available for legendary craft, should have been like this from the start
This. Its also why we are getting tokens, which will be tradable.