Yes, OP Skywars is fun and all, but you get bored quickly of efficiency 1337 picks and punch III bows. I think it'd make it more interesting if the following was implemented.
So here's my idea:
The Cubecraft devs have already demonstrated their ability to make items with custom enchantments, attributes, and behaviors, like the wither bow from SCB or the splegger from Splegg. I think it'd be super duper fantastic if we could have a super-OP version of Skywars. Here's just a few of the ideas that have popped into my head over the past week:
Wither Bow: A bow that fires wither bombs.
Ghast Cannon: A bow that fires ghast balls.
Blaze Bow: A bow that fires fireballs in rapid succession.
Hookshot Bow: A bow that catapults the user toward the target.
Lightning Bow: A bow that summons lightning on the target.
Mob Grenade: A throwable item that spawns a random mob, from squid to angry pigmen to ghast.
Flashbang: A throwable item that blinds anyone within range.
Jetpack: A wearable item that lets you propel yourself 5-10 blocks in the air. Uses up armor durability.
Lasso: A throwable item that ties the target to the player, letting you pull them off their island.
Giant Magnet: Causes all items on the ground to fly toward the user.
Airstrike Remote: A throwable item that lets you summon TNT up to 3 times.
Tank Armor: Armor that makes you move slower, but grants knockback resistance and extra protection. Ninja Armor: Armor that makes you move faster, but decreases knockback resistance.
Piston Gloves: An item that allows you to pick up entities and other players (and toss 'em!)
Anti-Gravity Weapons: Melee weapons that knock a player skyward instead of back.
Fish Bait: A throwable item that spawns squids riding squids, making an effective scapegoat.
Avalanche Summoner: Summons many falling blocks of different kinds above the islands, raining potential hazards and goodies alike on the islands.
Chaos Remote: Gives every player a random potion effect for 15 seconds.
Lemme know what you think, ideas and suggestions are welcomed, etc. etc. blah blah blah.
I very much support these as optional enables in Sky Wars (if they are practically codable). The only contentious point - as others highlight - is knockback resistance. Cheaters are a fact of the game and nothing should be done to make them harder to find. Otherwise, I think it is just a matter of how long these options actually take to make. For some (piston gloves) I imagine it is not easy.
n.b. for the lasso: I would just modify the fishing rod to have this behaviour.
n.b. 2 Avalanche - I have toyed with the idea of a layer of leaves with a layer of anvils above. As the leaves randomly disappear, the anvils drop down. I think this would be the easiest way to do it in practise.