Everyone enjoys training a skill. The first time. For skills that require no resources I think soulstones need a different update. Lets make it a vet reward for players that have done their time. Like 3 year old pick. The Purple Soulstone not only transfer any skill, it also can just copy a non resource skill to another charater (same account) You could keep your peace tamer intact and try out an archer paladin tamer without playing who has the skill now game. All the crafting skills would not get to be copied. Archery would get a pass even thought the skill burns ammo. Being a big fan of mining I would say mining couldn't be copied as soon as they put charges back on a lumberjack's axes. Skills that nake gains by burning regs (not casting spells, sorry scribe alky), ingots,leather/cloth and woods would not get the copy option.
Another option that could be on the Purple Soulstone has the ability to mail it through the SPS to another character on a different shard (not SP/Mugen). Could even charge a fee for using the SPS (Sosaria Postal Service). The ability to recreate your favorite templates (no Mule) on another shard on characters that have been properly scrolled up. Recreating a peace tamer on another shard is just not a good use of my gaming time. Once is enough per account. Like training then don't waste a vet reward pick.
Two skills would have to take some thinking if they can be copied. Poisoning and Lockpicker.