Hi, Junkrat player here, who also plays Genji, Reinhardt, D.Va, Torbjorn and other stuff too from time to time.
Junkrat is powerful, but to state that he is OP is rather stupid in my opinion. His various buffs have simply put him in a situation of viability at last, after months earlier in the game of being a troll pick in ranks higher than like Platinum.
The important thing to understand when playing a Junkrat is that he is extremely powerful at close range, and extremely good at locking down a choke point. He makes it very difficult to pass through tight spaces due to long range spam, and if you get close to a Junkrat he has all the tools to destroy you. Therefore, if close quarters and tight spaces are his strong suit, how do you beat a Junkrat? Range. Widowmaker, Hanzo, Pharah and Soldier 76 are extremely good against a Junkrat. It’s pretty difficult to accurately aim his pipes at range. Possible, mind you, but it requires massive skill on the Junkrat’s behalf to pull off reliably and repeatedly. Mechanical skill, of course, as I will touch on later. But basically, don’t walk haphazardly into choke point where a Junkrat is spamming and expect to live. Go through quickly as a team, with your tanks blocking the damage, and take the Junkrat on from range. Best way to fight him.
As mentioned, I also think we really need to discuss “skill” in Overwatch. Because Junkrat, Winston, Reinhardt, etc all require a lot of skill actually. But what they don’t require much of (Junkrat still does need decent aim to hit his pipes at mid-range though) is mechanical skill, aka aim. Most DPS mains that like to play Widowmaker and (try to) hit sick snipey shots don’t seem to quite understand that there is more to Overwatch than “Who can click heads best”. Positioning, Good Ability Usage, Timing and Teamwork are equally vital to being a good player, and Junkrat (amongst other characters constantly sh*t on for “wah no skill”) needs to have far better understanding of positioning and ability management than a Widowmaker ever will. So please, stop this stupid argument. You look stupid when you complain that Junk doesn’t need skill.
Now, his ult is a different story. I think that its a balanced ult, but that it maybe does charge a tad too quickly. Just increase ult cost for Junkrat a little, and I’m sure he will be fine. But then again, that might not even be needed. At high ranks Junkrat doesn’t reliably get Tire kills. Even in Platinum where I find myself most of the time, my Tire often gets blown up before I can blow the enemies up. Maybe try adapting to the faster tire and just… shooting it? Just a suggestion.