I know many players loathe the idea of having to create new gear for a new crafting tier, and believe me, I understand the prohibitive expense and time required to make a new set (nothing says, "Badash Dragonborn," like a non-dyeable leather diaper, ala the EP Heavy motif).
There are many though, who would enjoy the expanded resource variety, and are happy to always craft a new set regardless of the cost; so, I humbly suggest these ideas:
1) Allow players to "upgrade" their gear to the next crafting tier at the representative workbenches, keeping the old gear's rarity, but costing the full amount of the new crafting material, two style stones instead of one, and half the tempering improvement materials normally required for a fresh set.
2) As mentioned many times before, allow players to convert any motif style to any known style using the above cost, instead of for free like with Imperial.
3) Allow traits to be overwritten, just like enchantments, but use two (or more) trait stones, and necessitate a Master passive for Clothing, Woodworking, and Blacksmithing.
4) Finally, if a player wishes to change the set type in addition to or instead of the Style, I believe the cost outlined in point 1 would suffice; the player would just need to be at the desired specialty forge location when reforging.
This would encourage more build experimentation, and would embolden players to upgrade fully earlier.
Is this a good compromise?