Based on the few hours I have played, I think Bloodborne is most certainly easier than the other three Souls games by a fair margin. Obviously that could change as I'm still in the early goings but thus far my experience with it has been surprisingly laid back and I haven't experienced any rough beatings like some of the shit I suffered through in the other games. I find that this is mainly due to two reasons, and both involve the healing system:
1. health potions aka "blood viles" restore HP instantly. Granted there's a *very* small window where you're left vulnerable while your dude consumes the potion, but your HP restores instantaneously. This is a stark contrast to Dark Souls 2's healing items which not only left you vulnerable for longer they also took half a freakin decade to replenish HP. And these blood viles are plentiful as fuck. They're essentially an estus flask that can be refilled a infinite number of times without the need of a bonfire. There has yet to be a situation where I've completely ran out of them and most of the time I'm carrying near the max amount.
As if that doesn't make your hunting breezy enough, there's also...
2. the offensive healing or whatever the technical term is where, after taking damage, you can immediately regain that lost HP if you damage the enemy quickly enough. And I love this mechanic btw. I think it adds some extra depth to the already awesome combat and persuades you to perhaps play a bit more aggressively than you normally would. This has made some enemy encounters super cheesy though. Quite a few times I was able to blindly charge into mobs of enemies while swinging my axe around like a mindless fuckin idiot and then walk away with barely a scratch, because I was constantly dishing out damage while I was receiving it. That's something you simply CANNOT get away with in other Souls games.
Now I'm not claiming to be a veteran god when it comes to Souls because I'm not. I'm mediocre at best, and in the past I would often have to resort to summoning other players in order to progress through certain areas and bosses. In Bloodborne, I killed the 2nd boss on my first attempt with a base level 10 character (I took a wrong turn and accidentally skipped the first boss so I didn't have the ability to upgrade at this point). After that I went back to find the first boss, unlocking all the short cuts I might have missed and brutally murder-raping every living organism I came across along the way. Eventually I found him and murder-raped him, also on my first attempt. This was all within a couple of hours time, most of which was played through with a base level 10, and zero summons. I shouldn't be able to do that because I aint that fuckin good.
Aint no Souls veteran in their right mind going to claim that this game is harder than Demon's Souls, Dark Souls, OR Dark Souls 2. I can only guess that the reason for all of the epic struggles is because some people are simply going through the rough stretch of adjusting to the more offensive style of play. I think the thing is, at least with me, was that going in I had a pretty good idea of how this game is meant to be played (just what I gathered from previews and interviews and such) so I immediately left any grand ideals and philosophies I had about Soulsian combat at the front door, and immediately forced myself to adopt a more buck wild and daredevilish style of approach. I kept getting fucked up for a little while but eventually I found the groove and started coasting. There's really not much to it and I'm sure plenty of other people will start coasting too once they stop playing like a bitch.
All that said, I'm still loving the fuck out of this game. Thus far it's had some of the absolute best level design, artwork, atmosphere, and combat that I've seen come from this "series" since Demon's Souls blessed us with it's existence back in '09.