Okay? The hell does that matter? If your entire point is literally that somehow new canon overtakes the old in a series where Nasu constantly brings in the old canon to help shape his new ideas(I remember Nasu talked about ORT being the equivalent of a Bonus Boss that's stronger than the Final Boss... around that exact same time... Oh LOOK! FGO has ORT in it and he's superior to U-Olga Marie in every facet!), then I think you legit need to actually stop and actually read the series.
That's rich coming from the guy that has admitted to not having read a single of Nasu's novels.
Unless Nasu explicitly goes against that statement(like he did with Heracles and his God Hand when Takeuchi believed Nasu had it be completely impervious to whatever attacked it rather than gain a +100 Resistance), then no, Kotomine is still > Ciel at his absolute best, no matter if it's the Remake or the Original(Especially since the Remake heavily references the Original in many areas).
Ciel's demonstrated feats and scaling put her above Kirei at his prime. Kirei at his prime isn't even that much stronger than Kirei in FSN. He needs 10 Command Spells to defeat the weakest Servant in the 5th Holy Grail War, Cursed Arm Hassan. He can only defeat Servants that don't specialize in hand to hand combat like Assassins and Casters, needing good conditions like pride and suitability to defeat Servants that do specialize in H2H combat. His best objective feat is being compared to a basic ass Dead Apostle in combat ability.
Beyond her space laser, the fuck does she really do in the remake worth a damn? Haven’t had time to pick it thoroughly apart like I did the OG Tsukihime material.
Ciel has killed 4 Dead Apostle Ancestors. Ancestors are unfathomably stronger than basic ass Dead Apostles. DA's as a whole are stronger in Tsukihime than in Fate due to the Human Order being stronger in Fate worlds.
Ancestors are now even stronger in the lore because they have Idea Blood, their special superpower they get from being an Ancestor, whereas Ancestors in old Tsukihime had mostly random shit from abilities they cobbled together on their own and sometimes a Reality Marble that wasn't even guaranteed to be good in battle.
Rank VIII Dead Apostles, the Successors of the Dead Apostle Ancestors (Rank IX) are stronger than True Ancestors.
DAA and their Idea Bloods are compared to Divine Spirits and their Authorities.
Ciel has the strongest magecraft humanity has, equal in Mystery to Excalibur, a giant beam of light dozens of kilometers in size.
Can even defeat a rampaging Arcueid.
Remake Ciel has mastered every weapon, has been trained by a DAA, has all of Roa’s wacky shit and seems more frequent to bring it out, has way more church gear than before and the numerous Idea Bloods of the 3 Ancestors she has killed, which can give even Ancestors pause, etc
Bazett has better powerscaling than Ciel outside Powered Ciel being vaguely compared to 30% Arcueid in Melty Blood by a Kohaku battle quote.
Not really, even OG Ciel was stated to be too strong for a group of Sion, Tohno Shiki and Akiha to defeat. Sion herself being stated to have physical prowess that rivals or surpasses that of a Dead Apostle, which already puts her on the same level of Kirei at his prime.
I haven't even seen her being stronger than Shirou in any capacity considering Shirou even in F/SN can take a kick from Shinji Medusa and not instantly die, even being too difficult for her to kill without really going all out.
Nasu definitely loves going with the "More experience" angle which isn't honestly even bullshit considering having even 10 years experience over someone in a fight is a huge difference.
Shinji's Medusa? The same one that is so weak Zouken was confident Hassan could easily defeat? Meanwhile Bazett trades blows with Leysritt, who has a rank of strength matching that of Sakura's Medusa.
EDIT: Even if you wanna bring in "But Fragrach", considering how Fragrach even works, Kotomine from F/Z would demolish Bazett as he has no real "Trump Card" past Command Spell usage. He has no real technique past "Super Bajiquan" and that's basically a style, not a "Trump Card".
His usage of Command Spells is explicitly stated by Nasu to be a trump card.