Multiplayer, competitive EDH. Maelstrom Wanderer and why you might play it.

Throwing this up mostly as an example of what competitive EDH decks look like.

General:
1 Maelstrom Wanderer

Mana
Lands (35):
5 Island
7 Forest
2 Mountain
1 Tropical Island
1 Breeding Pool
1 Stomping Ground
1 Taiga
1 Volcanic Island
1 Steam Vents
1 Hinterland Harbor
1 Polluted Delta
1 Bloodstained Mire
1 Misty Rainforest
1 Wooded Foothills
1 Windswept Heath
1 Flooded Strand
1 Arid Mesa
1 Scalding Tarn
1 Verdant Catacombs
1 Alchemist's Refuge
1 Command Tower
1 Strip Mine
1 Wasteland
1 Ancient Tomb

Artifact Ramp (8):
1 Mana Crypt
1 Sol Ring
1 Mana Vault
1 Grim Monolith
1 Basalt Monolith
1 Worn Powerstone
1 Thran Dynamo
1 Gilded Lotus

Spell Ramp (14):
1 Tolaria West
1 Mana Drain
1 Sakura Tribe Elder
1 Nature's Lore
1 Cultivate
1 Kodama's Reach
1 Trinket Mage
1 Fabricate
1 Explosive Vegetation
1 Skyshroud Claim
1 Hunting Wilds
1 Ranger's Path
1 Garruk Wildspeaker
1 Tezzeret the Seeker

Business
Extra turns (4):
1 Temporal Mastery
1 Time Warp
1 Temporal Manipulation
1 Walk the Aeons

Removal (6):
1 Cyclonic Rift
1 Chaos Warp
1 Beast Within
1 Glen Elendra Archmage
1 Sylvan Primordial
1 Blatant Thievery

Search/draw (7):
1 Sensei's Divining Top
1 Brainstorm
1 Mystical Tutor
1 Sylvan Library
1 Mulldrifter
1 Rhystic Study
1 Intuition

Threats/beats (8):
1 Bribery
1 Knowledge Exploitation
1 Stolen Identity
1 Tooth and Nail
1 Avenger of Zendikar
1 Deluvian Primordial
1 Insurrection
1 Ulamog, the Infinite Gyre

Soft Combo (10):
1 Regrowth
1 Scroll Rack
1 Eternal Witness
1 Food Chain
1 Kiki-Jiki, Mirror Breaker
1 Deadeye Navigator
1 Mind's Desire
1 Spelljack
1 Palinchron
1 Defense of the Heart

Multiple (7):
1 Phyrexian Metamorph
1 Cryptic Command
1 Rite of Replication
1 Jace, the Mind Sculptor
1 Zealous Conscripts
1 Brutalizer Exarch
1 Hellkite Tyrant

How competitive EDH works:
Competitive EDH games are short. Very short. Figure the game is essentially over by turn 4. Someone will start taking all of the turns, assemble a winning combo, etc. Generally speaking, the first person who tries to do so will fail and the second or third will finally succeed. You want to be able to stop someone from going off maybe...50% of the time. The rest of the time, you just want to ramp as hard and as fast as you can into a game-ending threat of your own. Some strategies for this are better than others. Anything that moves the entire table back a turn (ie. Sylvan Primordial, Time Warp effects) buys you tempo at the table's expense and is very good. Anything that prevents someone from winning (ie. Glen Elendra Archmage) only buys you a fraction of a turn since stopping one player simply enables the next. Stealing tempo from individual players can be very wise if you're good at estimating who will be fastest and attempt to win first (ie. Mana Drain, Hellkite Tyrant). Generally, you want proactive answers that prevent combos from being assembled and turns from being taken, but you do not want people wasting removal on something like Stranglehold that could instead be preventing that first person from comboing off.

Why would you play Maelstrom Wanderer?
This particular strategy is very hard to interact with. Nobody wants to waste their own tempo countering your ramp, but eventually you use all of that tempo to drop a hasty beat stick who draws and casts two spells for you. Your nonland deck is roughly 2/3 threats to 1/3 dead-ish cascades...not that more ramp is a bad cascade, but you'd rather win.. The odds favor at least one threat hitting. This makes it very difficult to both counter your beater and your threat. Particularly if your threat is taking an extra turn, you have a decent chance of killing someone before they can do anything AND dropping additional threats. The "right answer" is something like Mindbreak Trap, which still lets you resolve a free spell and cascade again next turn.

There are better generals, though?
In a vacuum, Sharuum, Azami, Animar, and "5c" are probably the best. The Sharuum deck sports powerful tutoring, proactive control, and strong combos. Azami quickly gains monstrous card advantage (into one of several combos + extra turns) back by blue countermagic. Animar can toss out enormous threats relatively early, while backed by a strong toolbox control strategy. "5C" is general-agnostic and is essentially "good stuff" + Hermit Druid combo. In practice, playing these decks puts a target on your forehead. While some opening hands support playing archenemy, there's some value to being less conspicuous. Tier 1.5 decks like Maelstrom Wanderer, Krenko, and "enchantress" (usually Jenara) often fare better simply because they can lock things down or combo out out of the blue despite initially being a lower threat. Again, there's some value to only being second best.

This deck probably isn't perfect, what might you change?
Depending on your environment, you might want more answers to the graveyard and enchantress strategies. Devastation, All is Dust, Diluvian Primordial, and Karn Liberated are all fighting for the slot Primordial occupies. It's also possible to cut Ranger's Path for a silver-bullet answer to your meta. If you wanted to be greedier, there's an argument to be made for including Capture of Jingzhou. The issue is that from the first time you Time Warp just as an Explore, you've painted a target on your head by revealing that you're an explosive, fast build as opposed to a slower Primal Surge or Genesis Wave build. In theory, the inability of Capture to be misdirected makes it better than some of the other Time Warps I've included...but $200 for a white-bordered card...