I’m not sure I find this fair, but I’ll try to go through your objections as I can here.
Your first paragraph I will say is spot on - this is why again, I normally try to pry out narrative story elements, and frame the conflict in a way that ends up as a stalemate and in a way that’s more ambiguous.
One point that I will also add before I progress into your points is that I did retain as a requirement that we still set up Shadowlands - this requires that Sylvanas is secretly trying to increase casualties for her plan with the Jailer. The big difference? The Horde isn’t made to commit and then defend a genocide. It gets filtered through the usual faction war lens. From there we get to matters of motivation.
One thing that I omitted is that Night Elves generally get blamed for the Blood Ball - mostly because the naga infiltration gets carried away on lines of magical addiction - and while the naga technically struck first, the Night Elves ended up backing up who they thought was their person. This induces the Nightborne to join the Horde, in addition to Tyrande’s comments.
As you and others have stated, the Horde past this should have reasons to feel as though they are not and did not strike first. Genn just struck the Horde at Stormheim, and now he’s perfectly happy to let Gilneas play host to what is increasingly looking like a Lordaeron expeditionary force. I don’t see how you slice that in a way that makes it not look like a dagger to the Horde’s throat - and a threat they must reply to.
Regarding the feint and the Horde getting “facerolled” -
One, I don’t think that’s a good characterization given that they just charged through Ashenvale and won several battles.
Two - they don’t get “facerolled” - both sides take significant casualties, and that was explained in the post.
Three - Saurfang’s pincer arm isn’t there, meaning that the Horde offensive itself is at reduced strength when they are turned away.
Four - The nature of the attack in the War of the Thorns was a blitz. They didn’t hold territory behind them, they didn’t bother with supply. That’s canon, and is demonstrated by things like the Alliance getting to a mostly empty-Astraanar. Hence if it lost momentum, all of its gains would have been lost.
Five - This was implied but not directly stated - but Saurfang is able to hold things down in Kalimdor after this. The Horde holds this front in a stalemate (if we see this front again, it’s in Warsong Gulch content).
This leads me to why the Horde would divert to Lordaeron - this is a good critique, and I can mend the issue that it highlights by just indicating that Sylvanas diverts there - and is using existing forces that she kept there to deter the Alliance from doing what they’re doing, under the assumption that she’d have been holding Teldrassil hostage. This would have the added effect of reducing the size of the attack in Kalimdor somewhat - so perhaps with the feint we get 6:1 - but then the reinforcements show and even the scales given that Saurfang’s pincer movement is elsewhere.
This leads me to retort 6: If the Horde gets “facerolled” in Kalimdor, the Alliance gets “facerolled” in the EK - and I want to emphasize that the Blight only turned the momentum. The Horde in the EK, as I said, take apart the Alliance offensive and chase it all the way into Gilneas. Any future content in this area takes place in the Battle for Gilneas battleground or the Arathi Highlands Warfront.
I disagree that Saurfang would be cast as dumber in this instance. He has more reasons to agree with Sylvanas, and with no Teldrassil, no reason to worry that she’s going too far. Your concern with Saurfang feeling like a passenger I suppose is warranted, but I am coming up with this on the fly. 
I hope that addresses some of your concerns.
