Board Thread:Naruto Discussions/@comment-945885-20140820060530/@comment-945885-20140820062147

Obito united Senju and Uchiha cells in his body, so his sharingan is naturally going to be more powerful. He was similarily able to utilize Izanagi to its fullest, if you'll recall.

As for the Truthseeker Orb, I think the assumption is that it's always a combination of all the chakra types (otherwise its properties would likely change). They're passively generated and work more like ninja tools, so it doesn't necessarily mean that the user can actually manipulate or access all types of chakra on their own. That's how I interpret it, at least.