With 14 FSC runs I got 17 radiant fire crystals, they're 700ce for 50 at supply depot and ~11k-12kcr each at AH. Heating 5 star items require 42-102 radiants per level for 80% of the way to level 10. So my suggestion is to add a legit way to get radiant fire crystals without using a insane amount of time or money.
1. Add a crafting recipe - 5 shining fire crystals + 1000cr = 3 radiant fire crystals
OR
2. Up the drop rate to the same as other fire crystals
OR
3. Keep drop rate the same but have it drop in all tier 3 stratums
OR
4. Lower forge price to something reasonable
OR
5. Increase forge chance to something reasonable
OR
6. Lower supply depot price
OR
7. Increase amount given for 700ce at supply depot
OR
8. Do " " (it's your game, why is there even a suggestion forum)
OR
This thread has been made a million times and is pointless by now. They obviously don't care about it or they'd at least say something on the matter since it gets brought up like every day. But +1 anyway.