My biggest question here is what are restrictions actually for? Are they to bring problematic decks and metagames in line or are they a tool to shake up and create a metagame? It feels like, more and more, some people want restrictions to create a "better" metagame and to shake up the format. I've always said restrictions should only be used as a last resort.
Imagine if we restricted Dark Petition 2-3 years ago when people clamored for it. It would very likely remain on the restricted list for a long time to come, and nobody would entertain the idea that it could be safe. However, as we've seen, it's not even close to being a problem. It's ludicrous to even think about.
Vintage is the last place where people get to play all cards. While an argument can be made that restrictions still let you play with them, in reality this isn't actually true. Many cards are very playable as a 4-of, but completely unplayable as a 1-of.
Essentially, when cards get restricted, one of three things happen.
The card is so busted that is still finds a home as a 1-of in almost any deck that can support it. It can remain a card that people build around even as a 1-of. An example is both Tinker and Yawgmoth's Will.
The card sometimes sees play as a 1-of in decks but it isn't strong enough to go everywhere, but it has only a small presence in Vintage. An example is Gush, Memory Jar and Merchant Scroll.
The card is effectively "banned". What I mean by this is, the card can see play as a 4-of, but is essentially pointless as a 1-of as the card requires building around, and it's not worth doing so when you play a single copy. You might still see it from time to time but it's virtually non-existent. Examples include Windfall, Channel and Fastbond.
What I mean by this large rant is, when people want cards restricted, sometimes those cards actually get banned, for all intents and purposes, because it's not really possible to play many cards as a 1-of. Vintage is the last place people can play these cards, and I would highly prefer a very lenient restricted list in order to make this possible. Instead of making Vintage a format where you get to play with all iconic cards of MTG's history, many of them are actually "banned".
I get incredibly disappointed each time I look at the restricted list and see a number of cards I never got to experience in its heyday, and probably never will get to experience because of the way the restricted list is slow to change.
Vintage, to me, is not just about playing shiny new Standard Mythic with Moxen. There's nothing special about that. It's meant to allow cards from MTG's entire history. Instead, the way things are going, we'll end up with Highlander, with a restricted list stretching miles long.