Carlos, I've just explained why using Spark skins sometimes is absolutely impossible - they are literary order of magnitude bigger and slower then their Halo counterparts. This may be a weak argument in the light of how the entire framework is slow and bloated, but there are always certain requirements and at times it just becomes the straw that breaks the neck of the proverbial camel.
I'm not trying to protect Halo components in particular - I don't think they were better designed or anything. It just happened so by chance that they were smaller and there was a shorter tool chain that made it possible to skin them. I think that ignoring the problem introduced by the change is short sighted. There is a problem: a longer tool chain, a more complicated development process, a less optimal outcome - you can't really ignore that... Best. Oleg