I would like to add a few more things:
It is way to easy to stay in someone's DRS even if you are few tenths slower than them on raw pace. I wouldn't say that DRS/slipstream is too powerful but rather the dirty air needs to be increased or your tyres should start to overheat if you are following a car for few laps which would add some tactical aspect to the game.
That also brings me to another point - tyre saving is almost non-existent this year. You don't get punished as much as you did previous year when you try to ask a bit too much from your tyres, you will be better of pushing as hard as you can in almost every scenario apart from few tracks where the softs are hard to manage.
In real life, if you prepare a good exit out of a corner you are gaining time for the whole time on the upcoming straight that is not the case in the game. In game, you only gain a small amount of time for about 200 meters and it is not even comparable to what you gain in real life. This would make a cut back way more viable option to do when overtaking than it is now.
Teams should be able to do a double stop in pits without losing any time. As it now, you always have to pit on a different lap than your teammate, this becomes hard when it starts raining for example.
Also when you are in pits in qualifying for example and you are further away from the pit exit than your teammate and he presses go on track 10-15 seconds later than you, your team doesn't release you, they only do so after your teammate is out.
The grip on pad is ridiculous, I understand that the pad needs to be a viable option because there's probably a lot of casuals that play on pad or simple people who can't afford wheel yet there's no reason for the pad to have such a good traction and if there are people who want to get good at the game they should be forced to play on a device that is suited for the game.