I feel like Fate is one of those series that's more a matter of when than if, it's way too requested for them to just pass over. It helps that the main requests are against big characters that'd draw in views (Gilgamesh/Doom, Saber vs Vader/Luke/Erza, etc.).
just gonna copy n paste from a blog buy a guy name Pit the swordmaster that kinda sums it up with the series
"Fate may not be the most mainstream series out there but big it certainly ******* is, between it's almost frightening cult following and the sheer size of the franchise spanning so many anime series and video games across the last nearly two decades. It's no surprise that characters from it are requested very frequently to show up on Death Battle... and by that I mean uh... two, there's kinda two characters that just dominate on that front."
Gilgamesh vs Doom
could have been a safe bet for this season in a vacuum where Doom never went up against Lex... and this matchup didn't drop off a cliff in popularity... and uh, yeah a vacuum is kinda the only place you can really give it the benefit of the doubt because its odds nowadays are pretty pathetic, and sadly Gilgamesh' spread doesn't get much better than that.
The fact that Gilgamesh's second most popular and requested matchup is with a niche character very few characters even know exists and a series that really can't be said to be able to carry in views kinda tells you all you need to know about his odds from there. I'd
love to see Gilgamesh vs Sinbad happen but I ain't hedging my bets when Magi is fairly niche and Gil's not really a character I'd call marketable enough to pick up the slack.
Saber has it a lot better and she's got enough mainstream opponents to make her easily the likeliest candidate from Fate when coupled with her being recognisable even to non-Fate fans, anyone who's big into the anime scene knows who she is. While Saber's matchup spread is a jumbled mess of ideas that are all scrambling to be her safest bet, there's one matchup that had the brilliant idea to just step behind the finish line and walk forward... that awful analogy is trying to say she has one matchup that's likeliest to happen.
While, at least from my experience, it's a pretty commonly disliked idea in the hardcore vs circles, casually not only is Erza one of Saber's more recognisable opponents just by herself but she's also arguably one of her most popular and well liked matchups and Erza gets a fair amount of requests for a runback, helped out by some new stuff from Fairy Tail chapters that came after her fight with Zoro. Plus the research team seem to like it so... that's a plus.
THOUGHTS ON THE MATCHUP
Saber is one of those characters nobody can ******* agree on a good matchup for- Erza, Luke, Es, Darth Vader, Raphtalia, Aqua, Ky Kiske, ******* Optimus Prime for some godforsaken reason, and so many more and chances are slim you'll find yourself liking more than one, maybe two of these. As far as Erza is concerned, I see people either really hate it or... well not really love it, haven't seen a lot of that but moreso just tolerate its existence and I kinda fall moreso into the camp of just thinking it is there and doing nothing to capture my interest.