I stopped watching halfway through episode 9 of season 7, and the show was one of my top 5 favorite shows on TV still airing, so it is really as bad as you say. This is mainly the fault of Eric Wallace, who is the worst showrunner ever, worse than Guggenheim (Arrow's showrunner).
Season 1: 9/10 (Amazing, one of the best seasons of the entire show)
Season 2: 9/10 (As good as Season 1)
Season 3: 8/10 (Great season but the villain is less cool and there are less good episodes)
Season 4: 7/10 (Good season overall but mediocre ending)
Season 5: 6/10 (Decent first half with Cicada, Terrible second half with Cicada II)
Season 6: 5/10 (Decent first half with Bloodwork, Mediocre second half with Mirror Monarch)
Season 7: 4/10 (The entire season sucks)
If you look at the showrunner per season, it's easy to see the reason why the show got worse over time.
Season 1 was led by Andrew Kreisberg
Season 2 was led by Andrew Kreisberg, Gabrielle Stanton, Aaron Helbing, and Todd Helbing
Season 3 was led by Andrew Kreisberg, Aaron and Todd Helbing
Season 4 was led by Andrew Kreisberg and Todd Helbing
And then Andrew Kreisberg was fired by the production team of The Flash because of sexual harassment accusations, there were even men who accused him, so he was a bisexual predator. I'm not saying that they should have kept Andrew Kreisberg, but they should have at least replaced him with someone who was able to provide the same level of quality as before.
So then, Season 5 was led by Todd Helbing. It was still pretty decent in my opinion, except for the part with Cicada II, which was obviously forced gender diversity, but still there were some great parts with the Reverse Flash, which was my favorite character on the show, which Tom Cavanagh played so well.
But then, Todd Helbing had to leave because he felt like the show was preventing him from spending time with his family, he had children and wanted more time to spend with them and his wife, so he quit.
So, for Season 6 and Season 7, the CW chose Eric Wallace, and of course, they had no way of knowing what he would do with the show and it ended in disaster. And now, because of him, the ratings are worse than they have ever been. And there are only some fanboys/fangirls on Reddit who are blinded by fandom so much that they praise him, because most people hate what Eric Wallace has done with the show.
The main problem that the CW has is that it hires bad showrunners sometimes and instead of firing them, they let them stay, no matter how bad the ratings get. I have nothing against gender diversity, sexual diversity, or ethnic diversity, but it should never be seen as a replacement for good writing and a good cast of actors. The best actors of this show are mainly Grant Gustin (Barry Allen/The Flash), Tom Cavanagh (Harrison Wells/Reverse Flash) and Jesse L Martin (Joe West).
Carlos Valdes (Cisco Ramon) and Danielle Panabaker (Caitlin Snow) were also pretty good but their characters are being removed in order to be replaced by worse characters.
And the worst thing is that it doesn't take a genius to write good episodes of The Flash. Eric Wallace could have just given to the fans what they wanted instead of sacrificing quality for SJW politics and everyone would have been happy and the ratings would have been great. With the CGI that they have access to, it doesn't take much to make a fun show that lots of people will want to see.
The main things that are missing this season are (from most important to less important):
1) A good main villain (like Reverse Flash, Zoom and Devoe)
2) Good side villains (like Captain Cold, King Shark, Grodd, The Trickster, Pied Piper, Abra Kadabra, Vandal Savage)
3) A good cast of actors (The original main cast from season 1)
4) Enough episodes that focus on the story, and filler episodes should be at least more entertaining than those that focus on the story. Supernatural did this very well with episodes like "Mystery Spot", "Changing Channels", "The French Mistake", "Scoobynatural", "LARP and The Real Girl", "Ghostfacers", "Fan Fiction", "Yellow Fever", "The Real Ghostbusters", "Bad Day at Black Rock", "Time After Time".
5) Lots of action and only a bit of drama, but not too much so that it doesn't become a soap opera
6) Some progression of the characters, especially The Flash's powers and his speed should be getting better each season like how Clark's speed in Smallville kept getting better and better from season 1 to season 10. And if they are going to give lots of screen time to Allegra, then we should be seeing her using her powers a lot more, she almost never uses them. This show has great CGI that it almost never uses, and it's not like it costs too much because once you have the equipment for the CGI, it doesn't cost more money to add more since it is made from the computer, so they are just being lazy because the showrunner Eric Wallace is lazy.
7) More surprising plot twists throughout the season
8) Less useless dialogue and less cringey dialogue (with 45 minutes of runtime per episode, they should be able to do a lot more, even with their limited budget)
9) More screen time for the characters that people want to see (especially The Flash) and less screen time for side characters
10) More crossover events than just 1 per year. Crossovers are what people want to see, and since all the shows are filmed in the same studio, it shouldn't be very difficult to do it.
My prediction is that if the CW doesn't fire Eric Wallace, they will keep the show running until they start losing money, because although the ratings are bad, if they are still letting him run the show, it must be because they are satisfied with the profits, because the production of TV shows is always about making money, not necessarily pleasing the consumers, unlike in other industries, where public opinion would matter more.
Many people are so picky about the shows that they choose to watch that they will say that everything that the CW has ever made is bad, but the truth is that although it cannot match the level of quality of HBO or AMC shows, the CW is still able to make great TV shows on some occasions when they have a good enough showrunner. People often use Arrow and The Flash as examples to mock the CW but they forget that it's the same network which also made Smallville and Supernatural, both of which were extremely successful, so it's not the network that is to blame, it's the showrunners that the network picked. But even big studios like Warner Bros make that mistake a lot by hiring people like Zack Snyder or Joss Whedon to direct their movies, which makes them end up with bad ratings. I think that is because it is impossible to predict how well a showrunner will be, because even if you look at their history, it doesn't guarantee that their future work will be as good as what they made in the past since there are only a few directors who are able to maintain the same level of quality over many decades (guys like Quentin Tarantino).
I really wish the show either gets fixed or cancelled so that everyone can finally get what they want or just move on. And I am especially curious as to what will be Grant Gustin's next acting job after The Flash because he has a really good level of acting talent and he has a great singing voice too.
