Does it need doing?
Yes.
Then it will be done.
It is kind of funny. It reminds me of what happened with Superman, DC kept him out of tv because of the DCEU, and the tv side got to do Supergirl, when WB gave up on doing anything with Superman in theaters on for the next 5-10 years, imo, they let CW use him, but now SG already used all of his most famous villains, storylines and iconic moments. The same will happens to Hal I believe.
The only good thing that can come out of this is they giving Paralax to someone else.
I can't really see Jessica and Simon playing off Sinestro like Hal would. Maybe Guy, but it would still feel weird.
It's just weird putting Sinestro in a show with a bunch of GL's he's barely connected to or cares about. I mean, he helped make Simon a GL (technically) but that's it.
Nature of adaptations pretty much. Sinestro will always be at his best opposing Hal to me but his general status quo as a "Former GL who went evil" boogeyman can be juxtaposed well enough to fit a freshmen GL (presumbably Jess and Simon) if that's what they're going for.
Hopefully he's done better than the DCAU at least, he was a big fat nothing of a character there.
Americans have this strange tendency to adapt stuff and then make it in stark contrast to the source material in many ways, and I think it ultimately causes friction down the road. Adapting Sinestro without Hal Jordan...it's like, you can do that...but why?
In the end it will cause tension within the fanbase, because people are going to be like "why do they keep giving these underdeveloped characters Hal's stuff. Why not just use Hal?" And hypothetical people who become Green Lantern fans from this show would end up being misled, and those types of criticisms will be what they're greeted with when they explore the mythology and fanbase more.
Like...when Sailor Moon gets adapted, the main character is Sailor Moon. It's not Sailor Mercury and Sailor Mercury is in a relationship with Tuxedo Mask, but that's kind of how Americans would do things if they were behind it. And those Sailor Scouts would mos. def be getting their races bent all to hell. And all of that would cause friction and confuse fans.
When Sailor Moon fans get into Sailor Moon fandom from watching cartoons everything is normal and no one is greatly confused, and if they fight with each other, it's over the quality an English dub or something...it's never like the main Sailor Scout should be Sailor Mercury. It's just really weird, and I think it stems from laziness. The Americans often tend to want an end result without putting in the foundational effort. They want to use these characters instead of Hal Jordan (for whatever reason), but then they realize these other GL's were never built up sufficiently enough to get by without aping the stuff that was specifically meant for Hal Jordan's character.
And just to be clear, I'm pretty ambivalent to all these characters, but I do think the situation is weird and bad.