You might also consider further deck restrictions per shard in the deck. For instance, shards must be "extra" cards, meaning you must have at least 30 non-shard cards, and if you choose to take 6 shards, you now have a 36 card deck. Or, for each shard you have in your deck, the number of maximum cards you can have of an element decreases by one. So if you choose 6 shards, the most cards you can have in one element is 2/3 - 6. That means with a 30 card deck, you could have 14 cards from one element.
Restrictions like these are easy ways to offer more depth.
If the concern is top teams always choosing specific elements, you can adjust it so that teams can pick any team element each round, but it must not be an element they've chosen before. Their player specific elements are permanent, and they must choose their team elements before the match elements are randomly assigned. This means that there will be 10 rounds before a team can choose a team element they have chosen before. For balance/fairness, you make team elements secret until match elements are assigned. That prevents one team from countering another upon seeing their team element for that round.
Again, this format adds a lot of depth to the event, as you have to compare a team element's potential strength to what your opponent's might choose, but also try to preserve your best team elements for rounds you will need them.