This is kind of how I imagine a tutelage deck looking:
Really just a pure control deck, and the idea of having that is kind of exciting. Maybe its ultimatly better to run symmetrical draw effects with answers, but I don't know--just because an effect is powerful dosen't mean we should necessarily run away from it. There is a real danger in being reactionary to powerful cards that challenge a format and the way drafters approach a meta.
An established, polished cube is much like an eternal format, and textual shifts tend to occur slowly, either with the removal of cards or the introduction of cards, and the introduction of new impactful blood can breath some much needed freshness into a format. In some instances, this can carry emotional consequences, as a paradigm shift can be a net loss for adherents of a certain deck, archetype, or playstyle, who than end up crying foul as the decision results in a giant "feel bad" for them. I don't think this necessarly means the designer should hold back, lest their format become stale, and they should put some faith in the ability of their drafters to rise to the challenge, and transition the cube to a new state.
I don't know if this card is ultimately going to be too good, but I do suspect that its powerful enough to force people to change the way they draft, and to spawn a new archetype. That is exciting; and I think makes it worth considering, as it would be fun seeing people trying to break the new toy, going deep into pure control, or watching other players trying to out meta it.
That being said, you also don't want to overly condense a format, by making it where people ignore the metagame and just brute force their way to victory, and there is some danger of that from this card. The decks I posted above are built as almost pure answer decks, looking to extend out the game and exhauste an opponent. Most of the interactivity comes from matching meta answers with meta threats, and as long as the deck is doing that, its fine. Tutalage functions there as a supercharger to its basic game plan. However, if it gets to the point where it becomes turbo mill, than the deck is just ignoring the metagame, forcefully asserting its will, and condensing the format in a manner thats unfun. It should not be played in that instance.
Its main weakness in many cubes is that its approaching those metas on an axis they are poorly prepared to address: enchantment and graveyard. There just is not much in the way of strategic foils for a basic turbo mill strategy to encounter, which is why it runs the risk of not interacting meaningful with the metagame. Possible metagame relationships include opposing strategies that want to
fill up the yard, ample
enchantment defense, and decks that
want to self-mill anyways as a means to win.
