I think everyone is forgetting one thing... yes, currently, Splice onto Arcane is pretty much worthless tournament side... but from what I've heard, R&D is making the next few bloques a slower game... so instead of the insane speed of Magic The Gathering we've experienced, it will be a slower game, more important to interact with your opponent's board and less important for flyign that combo from the hand.
If this actually happens, when Mirrodin cycles out we should see some interesting possibilities with Splice...
It's a cool concept, but the cards are too underowered. Splice or arcane won't be competitive. Ever.
I beg to differ.
Isochron Scepter plus any low arcane spell provides infinite splicing. That means continually casting the same spells every turn. Very effective in my opinion.
Maybe if the scepter didn't have a target on it's head saying "Oxidize Me!!!11" then you'd have something. However, this won't work in any format at the moment and I think you're smart enough to realise this. Besides, what would be the kill? 3 to the dome every turn? Please.
Any artifact that isn't indestructible has a large "Oxidize me!!!11" or a "Naturalize me !!!11" or for you old timers, "Shatter me!!!11" or "Disenchant me!!!11" or every artifact in play with a big "SHATTERSTORM ME !!!11one one" target on their head...
Splice into Arcane one of the few balanced NEW card mechanics that I agree with. Because of the Isochron Scepter, it can become very broken if put under the right circumstances (just like almost any card... look at Megrim... usually sucks... till you start hitting them with Hippie's in the face every turn) However, what makes it blanced is that
A: You can't slice the same spell into an arcane more then once. Meaning if I cast say an Otherworldly Journy, I can't splice in Lava Spike 4 times with my 4 red mana.
and B. You have to reveal the card from your hand, which means everyone KNOW'S it's there, and can be ready for you to whip it out whenever you play an Arcane spell.
Broken? If you make it that way. Other then that, it's pretty balanced.
And Underpowered? I would say Lava Spike is pretty dang good... Sorcery Lightning Bolt? 3 Damage first turn is back with avengance!