Yeah, I have a feeling that, even though the whole point of having a level requirement on the ashes is to specifically stop the tier pass people getting a progression boost advantage, not having to worry quite so much about squeezing as much renown out of each zone as possible will still give tier pass people a little more flexibility with their leveling route.
I don't think the ashes will provide much of a boost, though. They said "+3% xp" and I imagine that its only about 10% fully maxed out. I see it more as some extra junk to pad out the season pass so they don't have to make more cosmetics.
I got the ultimate version so when the season starts will be able to tell you how useful it is for certain.
I think one thing most people are impressed with is just how good the free cosmetics look. Even in just act1 transmogs. The armour sets are high enough quality to rival any game out there.
Also, season pass, battle pass, whatever, tier skips are pretty much the standard. There's always a free pass and a paid pass and usually individual tier skips for a few store coins. Then if you finish the free pass you think you might as well buy the premium one to unlock all the gifts since you're sure to get all of them. Often, Apex Legends comes to mind where this is definitely the case, finishing the paid pass will reward enough store coins to buy the next one. But this wont be the case for D4, unfortunately. I don't think anyone who has seen a battlepass before will be confused.
Paying for expansions is something Blizzard has always done, but I do feel like it's a bit obsolete. Especially with something like WoW where they also want a subscription to play you'd think the new content would just be free. Still, I'm looking forward to the Valkyrie class, or whatever. Everyone feels like a holy knight is missing. While launching with a mere 5 classes is "Diablo" enough when you look at Lost Ark with its 25 it's a bit weak.