There was three layers of acceptance to it, too, to help it along:
First, in Fate/Stay, you don't learn Saber's identity until like 5 hours into the game. You're invested, that's like a full season worth of an anime, and that's in Saber's story-focused arc (and mandatory first arc). You learn to love "Saber", and then "Saber" simply gains a second name. There is no attempted theft or coattail-riding of an IP's protagonist. This buys a LOT of goodwill.
Second, multiverse theory is multiverse fact: There IS a male version. You meet him a couple times in the expanded universe. Saber isn't erasing the male hero-king, she's just another iteration.
And third, Saber does suffer narrative penalty for being R63'd: Iskander disrespects her for slacking in personal strength, Gilgamesh tries to own her (both in-character for their heroic eras of the past with women). One of her masters literally never spoke to her except to use command spells, because she was supposed to be male in-universe too.
There was three layers of acceptance to it, too, to help it along:
First, in Fate/Stay, you don't learn Saber's identity until like 5 hours into the game. You're invested, that's like a full season worth of an anime, and that's in Saber's story-focused arc (and mandatory first arc). You learn to love "Saber", and then "Saber" simply gains a second name. There is no attempted theft or coattail-riding of an IP's protagonist. This buys a LOT of goodwill.
Second, multiverse theory is multiverse fact: There IS a male version. You meet him a couple times in the expanded universe. Saber isn't erasing the male hero-king, she's just another iteration.
And third, Saber does suffer narrative penalty for being R63'd: Iskander disrespects her for slacking in personal strength, Gilgamesh tries to own her (both in-character for their heroic eras of the past with women). One of her masters literally never spoke to her except to use command spells, because she was supposed to be male in-universe too.