I recently watched Blackwater and WOTW and I have to say, I think Hardhome is better than both. Also I like WOTW more than Blackwater, which surprised me because I didn't really care for the episode when it aired.
Blackwater had a great build-up during the episode but once the Wildfire explosion was done with, they kind of blew their wad. It was a bunch of redshirts running on a beach in the dark. The budget limitations were very glaring here. And the return to the status quo at the end was pretty deflating as well. Tywin's arrival wasn't played up to the degree it should have been and came off muddled. Tyrion being betrayed by the Kingsguard was very confusing for many of the Unsullied and to top it off, the episode cuts off suddenly at the end with no warning.
My main problem is that it's a beat for beat copy of the Battle of Helm's Deep from LOTR with the same low stakes outcome.
IMO, WOTW has so much more going for it in terms of the number of fronts the battle is being fought on, the geography of the different entry points, the individual confrontations, the sheer scope of the attack and the enhanced CGI budget. If people rate it poorly, it's most likely because they generally find the Wall stuff boring. I don't so I'm not bringing that baggage in. As an episode that focuses on one set conflict, it's head and shoulders above Blackwater, which gets by mostly on reputation. When I rewatch Blackwater now, I find I disengage after the Wildfire explosion. Not much of note happens after that.
I went back and re-watched the Blackwater battle scene as well - to see if maybe I'd just forgotten how epic it was. It was pretty awesome and there were a lot of great scenes in there for our beloved main characters. But since then, the show creators have gotten a lot more savvy with fight scenes (well except for the sand snakes and we're just NOT going to discuss that hot mess!). WotW and now Hardhome have upped the bar quite a bit both in special effects and massive armies clashing. This gives me a great deal of hope that the next two season's massive battles, assuming the White Walkers begin their march southward, and Dany arriving with dragons are going to be truly epic.
"Well good luck, Ramsay. Will you fight shirtless with knives again? I hope your dick falls off."
"Jon carry your purse with you, goddamn!"
So yeah, Jon lost his man-purse full of dragon glass so now what are they going to do? Will the wildlings know where to get more of it? There aren't enough Valyrian steel swords left in all of Westeros to really help - though it's interesting you noted Brienne's got one of them that was re-cast from Ned Stark's sword so that's good - she's a big girl who could do some serious woopass on White Walkers - yay!!!