ok, I guess I'll have to be serious then.
The Ship
Half-Life 2
Oblivion
Morrowind
Return To Castle Wolfenstein
Doom 3
Call Of Duty 2
Rainbow Six: Vegas
Thief: Deadly Shadows
Dreamfall
Civ4
Warhammer 40k: Dawn Of War
S.T.A.L.K.E.R. Shadow of Chernobyl
Quake 3: Arena
and a shit load more.

$20 seems a bit too high for GoG. I'd say no more then $14.99 would be reasonable for compilations or games with expansion packs. At that price, we could see Ghost Recon get upgraded to the "Gold" edition or maybe even see publishers like Bethesda cough up a game like Morrowind GOTY with it's two expansions? I agree though, the higher price point should be used sparingly.

Eh.
The problem is - once you make that step there's no way back. Would you still pay $20 for any of these 5 or even 10 years down the line? I can't see publishers dropping down a price point as time passes. Not willingly. Not with further negotiations and pleads from GOG, really.
Also: In comparison to some of the real classic games ... I'd actually rate a number of the games you listed lower. What makes these games so special for them to deserve a higher price point then other aged games?
Technology? [It'll age - as with any other game]
Gameplay? [Subjective and debatable. I feel there are already better games on that end in the GOG catalogue then a number on your list.]

The first Outpost game should have been great but got released in a VERY unfinished state. Remember how many game elements were mentioned in the manual and strat guide that weren't even in the finished game. Outpost 2 was good, but I was expecting more of a "Fixed" version of the first game. Gameplay was a bit different in the second game. Anyway, back on subject.

almost all of them had a metascore of 80 or higher (the ship didn't, for sure)

As much as I understand the desire, I must say that I have some concerns about the chance of higher price points.
Remember that the publisher is choosing which of GOG's price points a game gets released at, and we have all seen a significant number of games released here at $10 that should absolutely have been $6. Give the publishers the option of $14, and a lot of releases will suddenly be $14, just because they can.
The $10 maximum is really quite a selling point of the service, to my mind. As such, it will be interesting to see what happens.

that behavior is not currently being exercised, there is no reason to believe that will be the case if a higher price point is instituted. Also, as mentioned HERE a higher price point could also cover game compilations. Instead of having to pay $18 for all of our fallout games, you can get all 3 in a pack for $14.99. Or something like that. But regardless, the publisher may set the price but gog doesn't have to offer it. Say if someone wanted to offer an old Dos game for $20, they could easily say "no, that doesn't offer the kind of value our customers want and expect." the publisher doesn't say "you'll sell this game this way, or else!!" or else what? they won't do business with GOG? fine, GOG wants to provide value to it's customers, and if I'm getting an appropriate amount of value, I don't mind spending more money.

All of these games can easily be found for 10 dollars or less in stores though.

I think he has a valid point though. Ubisoft quickly saw that the 10 dollar price point would get the the most profit, even though most if not all of their games should be 6 tops. If there's an option for more money they will take it. If GOG wants their, presumably large and important (EA), back catalog they'll have to sell at the prices the publisher wants.

No. That would only be true if you assume that:
1* Every publisher that used $12.99 would use $9.99 if only two price-points existed.
2* Every publisher that used $9.99 would use $12.99 if there we more price-points available.
3* GOG would agree to such terms without trying to negotiate a better deal.
I think 1, 2 and 3 are false assumptions. I can back this up by the fact that we have roughly twice as many $5.99 games as the $9.99 games, which would be next to impossible if everyone would jump on the highest pricing option that is available. This alone proves that the GOG team can get us nice deals.

I guess there's just something we really disagree upon. I do not take magazine ratings as a good indication of game quality. I used to read gaming magazines (starting, err, 20 years ago), but over the years proper criticism has gotten scarce. Most gaming magazines are too reliant on advertisement income and access to exclusive to be able to be unbiased. Game Journalism right now isn't much more than an extension of general PR by publishers.
Examples:
http://en.wikipedia.org/wiki/Jeff_Gerstmann
More on that one: http://www.1up.com/do/blogEntry?bId=8587828&publicUserId=4561231
Source: http://www.escapistmagazine.com/articles/view/issues/issue_71/409-Game-Journalists-on-Game-Journalism.2
And then - in line with that - the PR focus by publishers on Journalists themselves: http://www.washingtonpost.com/wp-dyn/content/article/2007/07/02/AR2007070201743.html
I find myself disagreeing with most reviews when actually playing games. Thought Half-life 2 wasn't by far an as big and amazing step forward as Half-Life one, for example. Half-life 2, to me, seems to have fallen in that trap that many engine developers fall into, too: The game made alongside is selling the engine, has loads of gimicky elements, but not a coherent, proper game play. The most interesting part of Half-Life 2, atmosphere and story wise, was City 17, in my opinion. But you are hardly in there and largely miss that really interesting aspect of the story - how the resistance actually comes together and turns into an opposition.
The biggest recent case of "game journalism" diverting from actual reception is Spore. Here's another game that reached that Meta-Critic 80% score. See user-scores in comparison. http://www.metacritic.com/games/platforms/pc/spore
Or, for one from your list, Oblivion. Nothing that I have seen of that game - screenshots/game-play videos/let's play thingies - makes it look interesting. The writing seems trite, the quests trivial. The AI routines pushed so much pre-release, don't seem to really add much to the game that the Gothic's didn't already do.
And then there's that question you didn't answer: Once these games are 10 years old - do you still think they'd deserve a higher pricepoint then games that are 10 years old, right now?

I'm going to give you a big YES! for the following titles: Return To Castle Wolfenstein, Call Of Duty 2, Quake 3: Arena (it's been more than ten years since release for that), Morrowind, and S.T.A.L.K.E.R., and Half-Life 2.

I couldn't disagree more.

As it stands, you'd have to pay more than $10 to get them new from steam, right now.

I would like to see all the series available here, rome, egypt, greece, china; even the two recent games. It's the same case for might and magic and HoMM fans: even if the last games weren't that good, it's nice to have them ALL available in one place, GOG.
Agreed.
And just see what Ubisoft did with the higher price tag here, I don't want that trend moving up to $14.99/whatever. For $9.99 we should get games and their expansions, for example ghost recon and its expansions, which would sell a lot at normal price here.
Sorry, but I wouldn't pay more than $9.99 for any of those games here, today. Sure they have their quality guaranteed. But even the first STALKER which is a great game, wouldn't attract so many people with a $14.99 tag.
And the premise that they are higher priced on steam is the same reason that *almost* no one buys them there during the week, only getting them if they are bundled like the id super pack or discounted.