I've participated in some of these formats before. They seem to have the problem of the strong decks getting stronger, while the weaker decks only get weaker due to the ante system. Having a good card get anted will frequently destroy weaker decks. Allowing the option of generating a new sealed deck does not address the fact that the stronger decks have already gotten stronger, and will likely continue to win. What if instead of ante, people play only for league points? There could be an additional option of them trading in 1 league point for a random card in the set (generate a sealed deck, then roll a die to determine which card they get).
If nothing else, we could always model this off the way MTGO does its leagues. Does anyone know how those work?
By the way, is there a way to buy extra land? Maybe 1-3 league points for a land pack (although the land packs in Apprentice don't seem to work)?
EDIT: Found some info on MTGO Sealed leagues.
What Is a League?
Leagues are much like tournaments that run over a period of weeks instead of hours. When you play league matches, you earn points that affect your rank in the league. However, wins and losses in a league won't affect your official Magic Onlineratings.
Each league runs for a minimum of four weeks, though some leagues may run longer. Each week, participants can play up to five matches that count towards their league rating. Additional league matches played during that week count only towards players' tiebreaker points.
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League Formats
League play is a form of Sealed Deck. You begin the league with one tournament pack and two boosters to build your deck. Each following week, you purchase an additional booster to add to your league deck.
You can find an example of someone's league experience
here.
This was a four week Mirrordin block league. To start, the person purchased a Mirrordin tournament pack (I guess that means starter, although it seems to give more lands) and a booster of Darksteel and Fifth Dawn. At the end of the first week, the person adds a Mirrordin booster. At the end of the second week, the person adds a Darksteel booster. At the end of the third week, the person adds a Fifth Dawn booster (SURPRISE!).
We could just use this format, or we could alter it a bit to fit in league points. Since there's already a constant influx of boosters, I don't think allowing additional boosters to be bought with league points is a really great idea. Instead, we could simply opt to keep the trading feature, and maybe add a buy-a-card feature (generate a sealed deck, people bid on the cards?). Or, to even things out, we could even scrap the league points system and go with a draft system, where the people with the worst records get the first picks (X boosters are generated so everyone gets 1 pick, and the rest is dumped).
In any case, I think league points should be kept seperate from the standings. For example, going into the last week, people may just decide not to spend their league points when they could clearly use extra booster packs, because they don't want to influence their rankings.