I think this is a really interesting idea, especially for someone new to the game who's trying to get into competitive play but who is struggling with some of the more spammy archetypes - both playing as (difficult to learn) and against (can be oppressive, bordering on NPE).
It would be nice if there was a way to also limit the CI/combo archetype as well for the same reasons, but I realise that could be harder to achieve and also people might feel that it starts to become too restrictive and they wouldn't want to play such a format.
1) Yes, I think an increasing cost for each new server you create (either overall or per turn - I'm not 100% sure which you're proposing) would be a reasonable rule to start to try to limit asset spam archetypes.
2) I'd definitely be willing to play in a league to test this out.
3) Anti-spam/Low-spam (or just AS/LS)?
Interested to hear others thoughts on this, especially from players more experienced than me (pretty much everyone!).