K so as strong as hec is/was there is plenty of ways to counter him. He will always have to charge through your frontline, and he will usually try to do this without his ult. So stop him. EZ. If he does ult, now hes stuck behind enemy lines, and provided that your front line doesn't let anyone else throught, Hec will be soloing 2 or 3 damage dealers. Unless you have fed him to the point of obesity, he is not THAT strong. Also, if you have ever played hecarim, you will know that champs with persistent slows and/or terrain creation absolutely destroy him. Azir's ult is easily the number 1 hec counter.
However, I will agree with you that matchmaking is in the toilet, and this is due to DQ literally destroying the ladder and allowing boosted trash to play with/against players so far out of their league that they simply cannot function.