Unfortunately, Brittle Splinter weapons aren't in much demand. The problem being when the splinter hits it causes the weapon to lose randomly between 8-18 durability points. Also, most PvPers don't want a hit area on their weapons due to them flagging on more then their intended target.
Splinter weapons in demand tend to have a high hit spell (your 70 fireball is great) & other mods like hit lower defense, stat increases, and regens. If the weapon is slow then SSI is generally a must. They need to be 'clean' however, so they don't wear out and can be repaired (prized or normal w/o brittle or antique). Hope this helps