Competitive Heroic aggro/tempo for modern. Fast, packed full of removal mechanics, card draw, and explosive creatures - plus Tamiyo. It can be explosive, but also survive the mid/late game.
Chucklefests to look out for include a T1
Lagonna-Band Trailblazer
followed by a T2 Twisted Image and Rancor to swing in with a sudden 8/3 trample on T2... or Rancor on
Seeker of the Way
on turn 3 alongside having him also 'fight' an opposing creature before swinging for 6 and gaining 12 life.
There are no cheesy damage multipliers or complex triggers however. This is a happy, simple beatdown which should consistently apply pressure game after game regardless of what gets removed or disrupted. The creatures are cheap and tough enough that a heavy removal strategy may run out of steam for the opponent.
I am considering picking up a 22nd land, but have not decided yet (there is enough draw that a turn 4-5 Tamiyo is realistic for example)
Lethal can be done on T4 through various combinations. T5 is more realistic however, as the deck is full of removal and interactive bits. Even Twisted Image can be more than its current role of pushing much more damage and drawing, acting as yet another removal piece against walls, mana dorks, and the like.
With Irresisible Prey in my experience effectively counting as removal itself in this kind of deck, often getting to the key creatures left behind, consider this deck to have 10-13 removal pieces (13 vs any 0-power creatures), with more on the sideboard if needed. Take into account that there is lots of draw, Rancor comes back, and the opponent will have a hard enough time holding your creatures at bay while you kill his: you will see the kind of fun you can have.
My concerns are: unfair decks, and combo decks which don't need creatures. For this, we have the counters on the sideboard, plus the Dromoka's Command can potentially shut down enchantment combo pieces. The Path to Exile is obviously on the sideboard for creatures too tricky to deal with by other means (and to block key equipped affinity pieces or infect dudes, and the like, for a vital turn), the Ordeal of Heliod is an extra 'screw you' to Ad Nauseum and serious racing decks, and the Stubborn Denial is there vs counterable board wipes and, most especially, potent planeswalker builds which can wipe.
Anyway, hope you like the build. I do believe it may be the strongest heroic deck I have shaped so far, and I have done a LOT of experimenting, in every colour.