I preferred Heavensward, personally. There are several reasons for this, but honestly, it can be summed up as this: Heavensward felt like it had a plan. Stormblood, notsomuch, to me at least; it feels like there's a lot of bait-and-switch going on.

I mean, look back all the way to Stormblood's trailer. Lyrics about a coming 'storm of blood' and build-up for a massive war. Annnnd... we saw fewer NPCs die, and generally saw less of an onslaught, than Ishgard was under. What gives? I was expecting a brutal expansion. What I got felt like a Disney version of a war, almost.

Or look at Zenos. I swear this whole resurrection bullshit feels like a developer said 'hmm, people were a bit upset that Zenos died so quickly - guess we have to bring him back!'. To say nothing of the god-awful shifting perceptions of Zenos: dispassionate ultra-powerful conqueror to bored cat playing with a mouse to a power-hungry idiot who basically sets a 'trap' even dumber than the one laid by Emperor Palpatine for Return of the Jedi. Come on, now. Pick one. Gaius and Nidhogg worked well in large part because they were given consistent core motivators that were then fleshed out over time. Zenos can't even make an appearance without me going 'wait, what?' at this point. It's like SE keeps kicking the can down the road, saying 'well, we'll provide justification for this later'.

Anyway, that's just my two cents. It feels like the Stormblood storyline is relatively aimless, sprawling, and unplanned. There are characters I like, and I like the broader story backdrop, but the execution is quite lacking. It feels like they're planning one update at a time.