If you feel Epic is too long, that tells me you prefer shorter games. My understanding was that non-standard modes are optional for those who prefer longer/shorter games. I support this and don't see a need to change them. Epic is a great mode for those who have been wanting to use high-cost cards that they can't reasonably play otherwise.
I don't like Merged deck, though, and will never play it simply because I hate the idea of building a deck only to have it diluted by another. I don't assume it's a bad mode, though, as some folks will enjoy it. I'm just not one of those people.
(BTW, it's Hyper and Epic, not Epic and Epic ;P)