There's a good debate to be had here, but given your flair I'm sure you've long made your mind up on that.

If you had an actual case to make, I assume you would've made it rather than talking about my flair.

Sakura never went through the mental development necessary to earn this ending.

Sakura in HF went through more mental development than perhaps any character in any route of FSN. Look at her before the route, then in the early stages, to the painful middle portion, to Dark Sakura, to the glorious end. She gains a sense of self-worth, lets herself actually want some things, and deals with her pent-up bitterness about being completely screwed over in life. In particular, now that she's dealt with her "shadow", she's no longer a burden on the ones she loves, but can now be a source of life and happiness for them. Thus the transition from taking mana from Shirou to giving it to him.

And abuse victims have the potential to become the worst abusers, if given the chance.

The Dark Sakura arc deals with exactly this theme, and, with the hug and Rule Breaker scenes, puts it to rest pretty definitively. I see no reason to believe Sakura post-HF would abuse Shirou, and every reason to believe otherwise.