It seems pretty clear to me that the leaderboard is made less legitimate by the fact that people can choose their opponents or choose the kingdoms they play.
I still don't understand that argument for chosing opponents. Of course people deliberately playing against sockpuppets is a problem, but that is obviously cheating. When I'm automatched against someone and play 2 or 3 more games with them on the table, is this also a problem?
If this was happening 200 years ago with the physical cards then of course players would play only in their phyiscal neighborhood, and then level 50 in New York would mean something else than level 50 in Tokyo, but that is not what's happening, IMO.
So to me it is not at all clear
that choosing an opponent will have an effect on ladder rankings.
For the kingdom, I can of course see that players that favour certain strategies could preselect the kingdom that favours that strategy. Again, this has AFAIK happened in the past and I think those games were made unrated.
But by the same argument, base-only games between players with no current subscription are also heavily different from games where cards are selected only from the expansions in the Silver or Gold expansions. Should rated games from the beginning of the service (so pre Nocturne and Renaissance) be made unrated because they don't represent the current "full game"?
I can kinda sorta see an argument for letting you choose your opponents, but allowing kingdom cards to be required seems way over the line -- especially considering that there was a new feature released (liked/disliked/banned card lists) that appeared to be the result of a discussion where what was OK to do in a rated game was talked about. Why go to all the trouble of making that feature if you can just specify a kingdom yourself?
The main difference is what you see when you click "Ready" and what you don't see. If you click "Ready" when the table rules are 'empty', but then the table host adds required cards to the Kingdom, you get unreadied, and can see the changes and decline to play or discuss with the host.
So the general idea behind this seems to me to give players maximum freedom to customize their tables, where all players can see those customizations and must agree to them.
OTOH, features with 'hidden' effects, like the banned and disliked cards, are restricted to not allow too much influence, so they can only contain 'a few' cards. This is unlike familiar cards, which can be heavily restricted to (in the extreme case) just 10 cards.