>>543043503
I think IP and SP are both fine and bannable. They're both very good but rarely feel too powerful. It's really just their material requirements and versatility that makes them great. Having versatile cards is a good thing and leads to more skill expression. Them being vulnerable to battle is also a good thing and leads to more skill expression.
But them being something any deck can slap on their endboard with any two monsters they have can be an issue. Largely the issue is that some decks can spam too much material too easily though.
Also as was already stated, they're cute so they should stay.