Probably, one of the biggest problems in Frontier is the bell-shaped distribution of power in MTG cards.
Approximately, cards can be divided into three groups:
(~5%)A, cards that you "must" play in a given archetype AKA pushed ones (hate this concept)
(~15%)B, cards that you may play in a given archetype, but that's not optimal.
(~80%)C, cards that you "never" should really play.
In standard, there is a deficit of A cards, so when building a deck, you put them all into, but that's not enough. You must decide what B cards you will put into your deck, and that's where variety comes from.
In modern, there is an overabundance of an A cards for most viable archetypes, so variety comes from picking what of them you should put in. Also, in modern, some C and B cards find their home archetypes, where they belong to the A group. Also, the sheer number of archetypes is overwhelming, and that's good for variety too.
In frontier, there will be (or is) an inevitable phase, where the number of A cards in most archetypes is approximately equal to the number of deck slots, and there is VERY LITTLE variety in deckbuilding. This phase will be over, but only when the format will become "another modern".
In short, ~94% of cards aren't playable in perspective, and this is very sad. For as long as a format has "pushed cards", it can only be - a standart, where everyone plays same OP cards, a modern, where everyone plays a different OP cards, or a "middle-phase", that is worse then both of them.
Play casual, or homerule-ban all pushed cards.