Now I know I am being trolled. At least two of those things you mentioned are desserts, not linuxes.

If it supports the uploading of the list of packages installed, then it might be worth it. Otherwise, GOG might as well just give up on selling games altogether.

Does it really matter if you get an old game with a Wine wrapper? I mean prior to official Linux support, you'd have to download the same old game, only the windows executable version of it. Having to deal with the bundled windows installer compatability issues on Wine or PlayOnLinux - it didn't always work and a lot of times actually created faulty installs.
Now you get the same thing, only a lot easier to setup and you don't have to worry whether or not you're using the correct version of Wine for the various games.

I understand and support the criticism with new games, that can quite easily be ported, but not with old games. More often than not, once a piece of software is over 10 years old not even the original creators have the source code anymore, especially not if the company they were employed in at the time, doesn't even exist any longer.

I think this is a prejudice. I've never had much success with what people called "the correct version". The latest version usually works just fine. Ok, there is a possibility of regressions, but that nowadays happens rarely. But, usually, it's more of a placebo. And regressions get fixed soon.

Theres always regressions version to version, and sometimes bugs are not fixed to the version after that.
As an example here's the latest wine devlog http://www.winehq.org/wwn/372
While theres certainly a lot of improvement going on, there are multiple titles on that list that simply stopped working for this new version.
And thats not a unique occurance, it's always going to be like this with a piece of software as complex as wine.

That data is taken from Wine App DB, which is not exactly always trustable. It's a user edited db, so different users give different marks for the same software/game. And if you look in the entries most of these aren't really changes. And some are connected to a software update - so, not really a wine regression. I looked into a few of these and not one was a real regression. ;) That doesn't mean there aren't any, just that perceived regressions and real regressions are not really the same and this kind of statistics are not trustworthy.