Self mill issues in jump in
Several of the Jump In! deck themes involve self-mill strategies but offer no option to bolster your deck with extra cards to prevent mill-out. I have lost to my own shoreline looter more times than i'd care to count; and unless drawn very early, vorinclex may as well not even be a double-sided card. This,of course, teaches new players the backwards notion that a deck should always conform strictly to card minimums rather than include a proper bulk and variety to accommodate complex strategies - a notion conceived during a time when the game was far less complex and card-to-card ratio really was the only factor worth considering when determining a proper card count. I get that new players should be discouraged from tower-building, but decks have no stated maximum size for a reason, and it's something new (and many old as well) players should be encouraged to take into consideration.