Hot take: I do not want RMC to be Saber BIS
Before you misunderstand me, I'd also like the infinite loop to make Saber Tier Negative, putting all the Tier 0s to shame, but that's beside the point. What I mean is that I don't find it "comfortable" that my beloved king with boobs BIS team has a member so sought after by other teams.
The Trailblazer is a character who can switch paths, which is problematic in this context, since if it's occupied with Seiba's team, the Reminiscence team will suffer (unless you have all the pink girls), and on the other hand, all Elation teams that can take advantage of the Trailblazer will be limited from the start.
Furthermore, it could also be a problem in the future, since when the Nihility, Abundance, or Hunt Trailblazers are released, they'll have the same issue. I know it would be a very distant scenario, but if the Reminiscence Trailblazer is ALWAYS Saber's BIS, it would definitely be annoying.
Another point I want to touch on is Cyrene, who has a combo attack with the Trailblazer. I know that using the Trailblazer and Cyrene together is a somewhat specific composition, but if what I'm saying comes to pass, that combo attack would completely lose its usefulness.
I also want to add the narrative point (I know it's irrelevant, but come on, those who want to have all four Fate characters on a single team should also agree with me here): it's strange that the literal protagonist of the story is stuck with a team of two random characters from another universe and a ghost hunter girl from Xianxiou, instead of with Cyrene (a character heavily shipped with the Trail Blazer by the Hoyoverse itself), with the Astral Express, or at least with a character who actually appears in the story instead of just in a skippable orange mission.
Obviously, I want Saber to be super meta, but I'd like her to be with a character who isn't literally
a character who can be on countless teams (or at least has the potential to be) and
the literal protagonist, because it diminishes their "importance."
Before finishing, I'd like to clarify a few things:
I'm assuming that the main team used by me and you will always be Saber, and that's why the Trail Blazer will always be there.
I know more characters might appear who could be useful to Saber in the future (Shirou, Sakura, or even Lancer in some way), but this is based on the assumption that RMC will always be BIS.
Sorry for the formatting; I can't separate paragraphs on my phone.
I know something similar is happening now with Sunday, Dan Heng, and Tribbie, but Tribbie (a highly requested character) can be replaced by Robin, and Dan Heng has been considered Saber's BIS character since his reveal (besides, Huohuo was there before him). I can't really speak about Sunday since I don't have him, but despite not having him, being a Saber main since version 3.4, I can say I haven't had much trouble. Also, none of them are the main characters.