The biggest problem with Restrictions in my opinion is that there are so many cards that were restricted, and stay restricted, with no real regards for how they interact with cards printed since their restriction.
You really want a spring cleaning? Wizards should come out and say, basically, **We are doing a grand experiment with regards to vintage. We are unrestricting every card that is not incredibly obviously detrimental to the game as it relates to the Vintage Format. We will closely watch the format and make adjustments via restrictions every announcement until the format balances itself **
I think the following cards could be unrestricted (WITH this theory in mind).
Lion's Eye Diamond
Thorn of Amythest
There is a VERY HIGH chance that many of these cards get re-restricted, but I'd be very interested to know what Lion's Eye Diamond could do in a format that has more than Force of Will/Duress/Mana Drain to interact with it, and I'd also like to see how Memory Jar would play out. Keep in mind, I'm not proposing this as a permanent solution - Wizards would just Re-restrict anything dominating every 3 months until the format re-balanced itself with a PROPER list.
As an FYI, this would be the new list to start with for my theory.
Chalice of the Void
Dig Through Time
Library of Alexandria
Wheel of Fortune
Flash stays on because of the interaction with Academy Rector.
Brainstorm stays on because it would be an automatic 4x in any deck that taps for blue mana, and would create what happened in 2007 again, where every deck was a brainstorm deck.
Chalice and Trinisphere stay on for their ability to create non-games.
Gitaxian Probe stays on because Free perfect information is bad for any competitive game.
The tutors stay on because of the other unrestrictions. I would love to unrestrict Merchant Scroll, but couldn't in a format with 4 gush and 4 fastbond.