Most of the replies I got dealt at least partially with the issue of world structure and warping, so I'll deal with those in general first.
On warping, it seems like a matter of carefully restricting where and when warping is possible, but this also depends on what warping gives access to. If warping is always how you access critical functions like weapon upgrading, cutting it off at any point is a huge problem. If they allow you to perform all critical functions away from the hub, that really weakens the hub's role in the game, which it seems unlikely they want to do. This makes me seriously doubt that there will be limits on warping. I hope I'm wrong.
The existence of a hub is a hairy matter. One obvious, massive issue is how the Dream Refuge's disconnected nature allows it to be a void of level design. Traversal is where a huge portion of the interest is generated in an adventure game, and there can be no interesting traversal in the Refuge; all the carefully constructed loops and knots of the outside level design are conveniently untangled into a dead simple row of tombstones to choose your reentry point from. This is fine for a game with the structure of Demon's Souls, where everything is disconnected, but it's a serious drag in an otherwise interconnected world. Even Majula was superior in this regard; at least it had physical connections to other locations and some interesting traversal as a result, though the amount was small. This leaves the Refuge without its largest opportunity for intrinsic value. There are other ways they could make it interesting and enjoyable to spend time in, but none are as powerful, and I very much doubt they could execute them well enough to compensate.
Unfortunately, it seems we're looking at a replay of later game Majula, where the only reasons to go there are for vendors of various types. Gathering all the vendors together seems convenient, but having to wait through a loading screen and do some basically nonexistent traversal (walk from warp point to vendor and back) turns that kind of hub into something players actually resent. In general, making a hub a vendor gathering place alone is weak design. Level design must always be the priority in a game in the style of Dark Souls. At this point, my thinking is that the designers are very infatuated with the idea of a safe zone to contrast with the rest of the game both gameplaywise and audiovisually, so much so that they're willing to force that safe zone in even when it doesn't help their broader goals at all. Maybe they'll beat my expectations completely and blow me away, but I'm skeptical, and disappointed that they seem to be letting an obsession with an aesthetic ideal that doesn't actually work get in their way. The Dream Refuge might not be a terrible detriment to the game, at least on the surface level, but it almost certainly won't be a boon.
I would hardly call running around with 20 estus flasks or 99 health gems 'near perfection'. Also, the guns were never meant to replace spell casting. They are essentially crossbows with the ability to parry. The arcane stat shows that there might be some form of magic that has yet to be revealed.
It's too soon to say as this is simply the beginning of the game. The first one is needed as you have to die to get your weapons and stuff and the second one is the first 'real' area of the game. Would you really want to walk all the way from firelink shrine to anor londo every single time you want to go there? Morover, it could be that we are only allowed to warp to specific bonfires like in DS1. We don't know how warping works yet and saying that it 'confirms your worst fears' is pretty silly..
You're right, 20 flasks was too high a limit and lifegems were a significant misstep. There's also the issue of humanity as a healing item. I was referring specifically to the first Dark Souls with that comment, and I meant to acknowledge its flaws with "near perfection." I think attacking that specific comment was a waste anyway, since all that counterargument implies is that I'm praising Dark Souls' systems too much, rather than that I'm wrong that Bloodborne's systems are inferior, which was my real point.
I realize that guns aren't meant as replacements for magic, I'd just very much like to see the amount of shots you're given be set and replenished at checkpoints the way spell charges were in Dark Souls (I imagined that you'd be able to increase the number of shots by upgrading guns the way you do standard weapons, and that they'd have their own robust upgrade paths in general). In that scenario I'd still be a bit leery about making parrying limited to a strict number, but this game's emphasis on dodging helps assuage that fear. It all depends on enemy attack design. I actually hope magic returns in Bloodborne, but exclusively as buffs/debuffs and tactical options (stealth, distractions, fall damage negation, etc.). No spamming the latest Soul Arrow equivalent to victory.
You're also right that we don't have a full picture of how warping works yet, but I'm confused by your comment about walking from Firelink to Anor Londo because that's actually impossible. Do you mean walking from Firelink to the top of Sen's Fortress? If so, with both of the shortcuts in that path active that's a rather safe path that takes a couple of minutes. I still wouldn't want to do that, but the path between the two lanterns in this footage is almost completely safe and would take only seconds to travel if the doors on it were already open. My "worst fears" comment was mostly in reference to the health and bullet systems, since those are now very unambiguous, while there are still questions about warping.
The biggest thing about the warping that I find makes it okay is that you seem to not be able to warp from lamplight to lamplight. You must first get to one then go back to the Refuge then choose where you want to go.
Oh no, now you've poked another hole in the scheme, I didn't even think about this. This is actually awful, it's functionally identical to being able to warp from lantern to lantern, but with a useless intermediate step. Shit, this is really something they need to fix if they haven't already.
I have heard that the blood vial vs Estus thing was a decision that Miyazaki deliberated hard over for a long time. Ultimately he went with blood vials because he thought it was the best decision for this game's design. Trust in his thinking, I suppose.
I would absolutely love to pick his brain over this issue. If you're claiming insider knowledge, I really hope you've cleared yourself with the mods.
So the ability to jump around from section to section ... kind of kept your sanity and made it easier to work toward progression. Each section was challenging, but you never got completely stuck in one zone facing the same enemies over and over and over creating that redundancy that can get people complacent and bored and frustrated and ultimately leaving, or restarting.
This is a really good argument for the Demon's Souls style of world structure. I think that the Dark Souls structure can have this advantage as well though, by having checkpoints that are surrounded by serious threats, thus trapping the player, be rare. I mentioned the "normal" route through Blighttown in my earlier post, and it's true that that experience, though rarified in the context of the goals of the game, can forcefully push some players away. In the end it's about the balance achieved in the specific level design. In cases where players can be trapped, the way forward needs to be challenging enough without being too challenging. I guess that's kind of stating something obvious and generally applicable, but it goes to show that the most fundamental aspects of design can be both very broad and incredibly subtle.