Substitute the word Necropotence for FoF in the above post by Thug and see if it is logical to unrestrict Necropotence.
Nope it isn't, cause when you replace them my logic fails, since Necro actaully is fast enough to beat those combo decks. And unrestricting Necro will distort the metagame.
Many of the decks you post are combo decks. An unrestricted FoF would almost certainly result in more control decks in the field and therefore it would make a metagame that is less attractive to combo decks. Although FoF in itself is not a huge problem for combo, a slew of control decks is. (I accept that combo does not auto-lose to control anymore but it hardly what you want to get paired against if you have combo). Note that FoF increased the chances of a control player finding that second FoW or the sideboard answer to your combo.
Actually I'm very happy to get paired against Control with TPS: Control-Slaver and 4cc are favourable matchups, Mono-U is hard but winnable and Tog is somewhere in between.
I think people will move TO combo when we get to see more of those control decks, both Dragon and TPS seem to have more than decent changes agains these decks.
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I'm not sure if anyone thinks that Voltaic Key should stay restricted, I think that it's still their because of a lack of interest from the ones managing the restricted list. And after all, unrestricting it will most likely have zero effect on the metagame, so It's not the first thing to worry about.
Koen