First look is -It lacks resistances; -Darius generally opts for either Cleaver or Tri force, not both;
Darius is a bit too clunky to be a good mid laner, especially with anything that has range or kiting potential. Might be a decent counter pick into assassins, but most will be able to harass him freely and force him out of lane.
I wouldn't build him differently than in top lane, except maybe hexdrinker if you're in a bad matchup vs. an AP. But either way, doesn't seem like the best pick and still works best in the top lane in my opinion (or bot lane since just about anything works bot now; with a good support).
I think this has potential to counter stuff like talon and zed but it should not be played normally. This build has an extra 20% cdr with it and the trinity and then cleaver is not the best itemization.
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(in yoiur case cause illaoi but buy it much earlier) its not realy good cause you dont have gap close abilities and you probably ended up flashing them but it can work if you gank hard the other lanes.