We hate Darius (TL;DR included, do not fear the text wall)
Well aware. Gotcha. Permaban. Even though I honestly think that he does have solid counterplay (while heartpounding, absolutely), totally broken as shit. Not here to argue.
But - a lot of people don't realize that the reason he's so OP is because he's like a shittier Riven - he gets food and snowballs to high heaven. The reason he's shittier is his early game is a big pile of moldy dicks sandwiched between two massive turds (I mean, there's worse early games, but unless he's facing a squishy melee champ he's pretty bollocks early).
So there's people who feed with Darius and suck anus in games. Happens all the time. Happens to the pros. Why? Because people haven't figured out that when a Darius is in the game, the beginning of it is supposed to be about him now, not the sucker ADC'ing in bot. Unless that bitch is going to be a wall of armor-shredding, damage-eating, bleeding-out-the-ass-causing, true-damage-slinging titan of terror, you're going to want to put your focus into your Darius early.
If you're still not convinced ganking for Darius and getting him fed is a good idea, well, here's some more motivation - unfed Dariuses are absolute shit. They're a bigger liability than a 0/10 Vayne. They can't take a hit without bulk and they can't do damage if they can't stick out enough shots to the face to activate his Noxian Might. And if you guys haven't figured this part out yet: his Noxian might giving him massive amounts of bonus damage as well as immediately maxing his stacks on hit is where his power comes from. It's his entire power budget right there - his R does mediocre true damage compared to others of its kind without it, he takes forever to apply stacks of Black Cleaver without the bleed damage stacking that shit, and you're not even going to 1v1 with your carpel-tunnel hindered attack speed if you don't have that sweet, sweet bonus damage to back it up (oh my god it's delicious).
So that brings us to the question: How do I, as the mighty Derpius, slayer of all the dinguses too stupid to ban or pick me, get super fucking fed? Well, you could go to your natural lane in top - but the fuck you gonna do up there? Keep trying to kill the same one cocksucker that's been cowering under his turret all game? Never going to get fed that way. Plus if you push it'll take you forever to walk your fat ass back to your turret when the jungler inevitably ganks you because your early mobility is beaten by pre-rework Xerath during his W.
No, that's not what you want to do - what you want to do is take this mother-trucker mid. Do it. Shit's sweet. Yeah, you're going to get flak from your team for going Derpius mid - who wouldn't called you a fingerjerking cockweasel? Most people wouldn't because that's not even a good insult. But seriously, fuck them because you just got Derpius past the pick-ban phase. You're goddamn king of the nerds at this point. So you go mid and guess what's going to happen? Mid's gonna get a cocky demeanor about them because you just countered your stupid self - here's them pushing wave to harass you. What's that? Your jungler's forced to gank mid because you're "losing"? Oh good, then that means BAM, a flash engage with two of the most stupidly strong slows in the game! Honestly, if you don't get a kill out of this then your jungler's special or has like no damage. Or maybe you suck, I dunno.
Now you got Phage. Niiiiiiice. This time, same thing - get them with E, but instead of having to flash, now you kill a minion, get that flat 60 movement speed boost and run up to that immobile bastard and E them in for a reking between you and your jungler. Because honestly at this point if the jungler hasn't realized that you just opened up a buffet for them mid, then they shouldn't be playing the game - they should be coloring the connect-the-dots duck they just "drew".
But now the mid-laner's hiding under his turret like a bitch - no clue how you're going to get them out long enough to murder them, and you're still too squishy and immobile to dive they aes. How the shit you gonna continue getting fed?
Well, what if I told you that in mid-lane, you have not only one, but two lanes that you can gank by just fucking walking to them? Holy Jesus you just hit on a gold mine. You waltz your fat ass down to bot - because for a jackass wearing absurdly huge armor you have a pretty high base movement speed that's perfect for roaming - and start to snowball your other lanes with you. And the best part is you're a goddamn fed Darius, so who's going to win the fight? The cocky-ass Caitlyn? Fuck no! Dunk her! Dunk her right in the goddamn face!
And you don't even have to use teleport. Guess what you can do? Teleport back to lane? Teleport up to top and snowball that bastard now, too? Choice is yours, bitch - the enemy can't do shit because you're the derpiest Derpius to ever derp this side of the Summonderp's Rift. Good job - you just snowballed your team out of control and are basically dragging your team to victory whether they like it or not.
So the point of this is simple: Take Darius mid. It'll ensure your jungler is "forced" to gank for you with some of the best follow-up you could ask from a champion in the game and you'll actually be able to snowball instead of rot at top-lane. Your jungler also maintains dragon control this way instead of picking and choosing (which he'll usually pick dragon over you because they're pretty clueless about how important feeding Darius is), and once you're fed you can go snowball your other lanes with easy access to both without teleport. Additionally, you have shorter walk to lane, a shorter lane for the enemy jungler to try and gank you (while having more sides, you generally outspeed a lot of mids and even some junglers), and even if you're under turret your W has a mana/cooldown refund built into it to assist you farming. Sustain out the fight, hold tight for when your jungler wants to make a play (or if you're feeling ballsy, see if you can't start shit yourself), and dunk, baby, dunk.
Go forth now, ye users of the broken arts, and derp like you've never derped before on Derpius!