I mean, if you disagree with the expectations that's fine but i don't think they're unreasonable. It's like if i bought a can of beer from my favourite beer company, took a sip and there was orange juice inside. Turns out the company's switched to producing oj instead. Sure it's gonna quench my thirst, but i'm not gonna get all the fun extra things that came with drinking beer. So i'm disappointed because i wanted a beer from my favourite company. The company's done nothing wrong, i'm just a little sad.
Aphex Twin is not a production line based company, he's an artist. There are musicians who work this way and release another album in the comfortable old style (AC/DC and others), but I have never expected Aphex to be this type, as with Squarepusher and others of that ilk. I can be disappointed too if it's not quite what I hoped, but to expect it to match my own invented / preferred ideal is unreasonable.
At no point had Aphex ever promised or advertised himself as a beer supplier: we get to drink what he serves (and I prefer OJ to beer anyway). Syro wasn't what I was expecting*, along with certain other music he's made, but then, there was never any formal customer / supplier contract stating what I was to receive. I can lump it or leave it, I can be sad, but there was never any promise made to be broken. Any promise was in my head and nowhere else.
*although I love it just dandy now**, having erased my own expectations and come to love what the album is, not what it wasn't
**sounds better on vinyl***
***imo
I started listening to Aphex Twin when drukqs came out and love everything he's done (icbyd is amazing!) but I must admit that I listen to the Analords and everything after mostly nowadays.