Bleach: Hollow Flash

I believe that the attack boost should be lowered and the reiatsu boost raised, in order to allow for the varied play style that the ability to steal Shikai implies it should have (especially given that the canon example of this was Kaien's Zanpakutou, which is a reiatsu-based blade).

Also, possibly, halve all of the boosts and have them gain half of the boost of any Shikai they steal.

I also believe it would be interesting if you could tag a Shikai for use outside of your Ressurecion, perhaps with special perks related to it.