How restriction decisions are made is much more important than what exact cards are on the list.
I would be interested to hear what Vintage players believe the foundational principles of the format to be, and they think how those principles should be expressed as restricted list criteria apart from specific cards.
This is a tough question to answer. I've only been playing Vintage for around 5 years so a lot of the way I consider the format is shaped by the cards which already existed on the restricted list when I started playing. Having said that, I believe there are cards on the restricted list now which should not be restricted - both cards which should probably have been unrestricted before now and cards which I believe have been incorrectly restricted over the last 5 years.
Having said that, 'cards which are currently restricted but probably shouldn't be' is probably an inherent flaw in the way the restricted list works. Cards don't exist in a vacuum. Power level is not something which can be assessed purely based on a card's intrinsic attributes - a great deal of a card's power level comes from its interaction with other cards. As a result of this, metagame concerns will always form a part of why a card is or isn't restricted.
With that in mind, there are several things which we can say about the restricted list as well as the cards which ought to be on the list.
First, I think the restricted list ought to be as small as possible. Different formats exist for a reason and part of the reason Vintage exists is to allow people to play with as many different cards as possible. Of course, other formats already achieve this aim fairly well. So, I think a distinguishing feature of Vintage should be that it allows as many cards to be legal as 4-ofs as possible. This then means that Vintage as a format should allow for the maximum amount of power, too. As has been argued before, power peaks in a format always result in playability vacuums (I use the word playability not in its strict sense, but in terms of being competitive, or something of that nature). Thus with more powerful cards in the format, the number of cards which are competitively viable is considerably reduced, but I consider this to be a part of the function of Vintage as a format. I also take this to be a very positive aspect of the format.
As I said before, power level is something which fluctuates. As such, I don't think it is particularly useful to restrict cards based on how power level is perceived. Having said that, I believe that Magic is a game which ought to be some number of things: Magic should be interactive, Magic should be skill intensive, Magic should provide some level of complexity and Magic should be about decision making. I believe the restricted list should be used to shape the metagame so that Vintage tends towards these things. With that in mind, I think that restricting cards which cause the metagame to tend towards uninteractive decks, for example, is a valid and reasonable way to use the restricted list.
I should acknowledge that the terms 'interactive', 'skill intensive' and 'complexity' could exist in various iterations. I also take this to be a good thing. Nevertheless, cards can exist which push the format towards or away from these properties, or some subset of these properties. Cards which push away from these ought to be considered for restriction.
For example, in order to make a decision, one must be presented with a decision point. More decision points will often result in a higher level of complexity and thus a more skill intensive format. As such, cards which reduce the length of the game by a drastic amount are unlikely to work towards these aims. By this reasoning, cards which help prolong games are preferable - especially if those cards also present several decision points of their own.
One of the most important factors in Vintage is the money players have invested in the game. Certain cards represent a tremendous investment in Magic and should be considered particularly important to keep in the format as far as possible. I'm avoiding speaking about any cards in specific, so I won't say anything further on this point.
Possibly the most powerful resource in Magic is mana. As such, I think that cards which provide an advantage in this regard whilst also being easily accessible for all players in the format are the cards which should be considered the most likely to be restricted. These cards are also the ones which I think should be the least likely to be unrestricted.
The restricted list is a very powerful tool available to the DCI. It has the capacity to be a very good thing, but it can also be a negative feature of the format. I think a negative aspect of having a restricted list which is too big is is that it would lead to more games being decided by one player drawing their restricted card. I believe this is something which should be avoided.
Finally, I would like to point out that the restricted list has a diminishing return as Magic ages. As more cards which provide a similar effect are printed, the restricted list's capacity to restrict that effect's presence in the format diminishes. This is something I think is a logical limitation of the format and of the restricted list. I don't think there is a way to fix this without changing one or more of the fundamental principles of Vintage.
I don't believe that the points I have made above are exhaustive. I would like to point out that I don't value all of the points above equally. Some are more important than others. I welcome any critical comments anyone has on what I have said above.