That post doesn't explain anything. None of these shows plan things out as far in advance as people are asserting. It reads like someone looking for patterns and reason where there isn't any.
Think of it like the structure of a book. You have a beginning, middle, and end. Now apply that to the seasons. You have Season 1, Season 2, and Season 3. Season 2 for tv shows is almost always a fan favorite because they have nearly a blank slate but with characters who are already established. Everything is in place to shake things up. Season 3 is the end. Look at the S3 finale, it was Oliver driving off into the sunset with the hopes of a better life. You could have a series finale like that.
The problem that Season 3s usually run into on these genre shows is that you're going to start having relationships bump into each other, maybe for the second time. Usually S3 is the one that closes the door on a lot of character arcs that have been running through the show...except we need to come back for next season! They have to tightrope walk between having a huge build up with finality, and making people want to come back next year. It's almost doomed to be unsatisfying in some way. The end isn't an end.
And I highly highly highly doubt they're going to use Flash to erase things that have occurred over the past few season of Arrow. Namely because not everyone watches all the shows. Yeah, we'll get a big crossover. Might even introduce some huge elements like Supergirl, but they're not going to make it erase "Olicity" The shows don't work with enough synergy between them on a continuous basis to make something like that work. They're not comic books.
I agree with the assessment that a TV show is always going to be an imperfect medium. Things during production can change suddenly, or audience reacts differently to how you think and sometimes a guest star just is good enough you have to bring them on and sometimes you have blindspots to certain aspects of the show you still keep on. So you have to just make do sometimes, especially if you are doing the 22 or so episode season runs.
But honestly I think planning is still a problem for these shows. Like I feel like they don't even agree on vague details until it comes down to it sometimes. Like who was in the grave this season. If they knew from day 1, yeah, keep it a secret but then you can use that fact to spend more time developing Laurel for those episodes before she's taken away.
It's like the finale tries to cram it into us - everyone misses Laurel and they saw her as the best of them. I don't necessarily agree with that but okay, they tried. I wish they tried harder by making her the glue that held Team Arrow together through most of S4, in spite of things like Oliver and Diggle's fractured friendship, or Thea going crazy post-Lazarus pit. I mean, those things
were there and Laurel was there to lend helping hands to those arcs, but it's just that maybe I don't think the show really tried too hard with them. They didn't have a clue they were gonna kill her until it was maybe a bit too late to do anything but work around the extra episode after her death.
Which is a shame because something like that could've easily worked in their favour.
I think overall on a per-episode basis Arrow definitely beat The Flash this year, if we're just going by what was more enjoyable to watch. But I think both shows kinda fell flat in the overall longer-term stuff. They need to work on that coming up. Arrow especially in the flashbacks. This year was inconsequential. The sad thing is that Arrow probably has a better thematic arc because they have those flashbacks, but they've been wholly ignored and feel like just random plot that happens and we watch piecemeal instead of it contributing towards, well, Oliver's development over the course of the show. We're supposed to be - at least in the first five years - his change from frat boy to survivalist to vigilante to hero. I feel like yeah you don't need to map it all out but I got the impression that they didn't even really squeeze in much effort this year. Like it was worse than S3's, by a country mile.
Green Arrow in comic has traditionally been somebody who tends to avoid killing, but when pushed he has no problems straight up murdering if he has too.