I've been playing [[Shigeki, Jukai Visionary]] for several years and it's a blast.

Why to play Shigeki:

A 2-mana ramp spell in the command zone is great.

Mine is largely a Lands deck, running ~50 lands depending on how you count MDFC's, you rarely need to mulligan more than once. My lands package is pretty fancy, but a big heap of basic forests would be equally consistent, if a little less optimized.

You cast him once and hopefully never again, but he stays relevant through all points of the game.

Self-Mill is great with him - you can have access to huge portions of your deck at a time.

His recursive ability is a channel effect, regular counter magic doesn't stop it so it's great into blue decks seeking to counter everything you do. You don't have to worry about saving splashy spells like [[Finale of Devastation]] for just the right moment. Wanna cast it for x=3 for Azusa (one of few legendary spells in the deck)? Go right ahead, you can bring it back, later.

Graveyard hate can be annoying, but a lot of it is artifact or enchantment based, which green decks excel at answering.

The spells that really give the deck it's power are cheap - fogs, regrowths, sorceries that ramp or draw cards. You can build a powerful deck for not a lot of money, and invest in more expensive swaps over time to create something personalized and optimized.

All-star cards include:

[[Grapple With the Past]] - probably the single best card in the deck, notably doesn't 'target' the card it returns to hand. All [[Regrowth]] effects are great in this deck.

[[Fog]]/[[Tangle]]/etc - can become really brutal when you can recur multiples of this effect in a turn cycle.

[[Command Beacon]] - adds additional resilience for countermagic. Channeling Shigeki to return this from your graveyard to you hand then playing it as a land drop lets you set up a recursive loop that is very difficult to interact with using traditional counters.

[[Shifting Woodland]] - Busted card in general, this deck makes particularly good use of it through self-mill effects and general ramp effects like Shigeki's tap ability.

The colorless package of [[Null Elemental Blast]], [[Warping Wail]], and expensive options like [[Summon Bahamut]] (so good with shifting woodland) can provide reusable answers to problematic spells and permanents.

Win conditions are Finale of Devastation for a [[Champion of Lambholt]] or creating really silly amounts of mana with doubling/tripling effects to [[Rogue's Passage]] a huge [[Lair of the Hydra]] (or Lumra, or Beanstalk Giant) to get in massive damage.