I always saw Borderlands (story wise) as smaller stories involving characters and situations connected to a bigger overall story. In BL1, it centers around this backwater planet that had been left ruined due to corporate greed, and abandonment, that supossedly contains a secret alien Vault that everyone is after. You are introduced to various characters, concepts and lore, but there isn’t a ton of great story. It’s a small story taking place in a much bigger universe. The DLCs do some more story building as well.
Bl2, you have the story of Jack and Angel, which connects back to BL1 and it’s characters and what Jack is trying to accomplish and you get some of the WHY. There is more universe/lore building in the side missions, echo logs, DLC and etc… Just like the first, its a small story told in a much bigger universe, and you start to see things kinda getting ties together.
TPS fleshes out jacks story more in the main story, and per the usual, we get more lore/universe building in the usual means, like the first 2 games. Its still a small story, without tons of answers to the big questions about the ever growing lore of the universe thats being created. This is the running theme so far.
TFTBL is a different kind of game, but the storytelling is every bit the same here. Small story about specific characters, with various bits and pieces to tie it to the other games, expand on the lore created and set ups for the future games.
So far…all of this continues to be the case in BL3. Nothing has changed. Honestly, I just think people were expecting more because it took so long, and they kept calling it “THE BIG ONE”
From my perspective, how this game was designed…I’m willing to bet their DLC and post release content will serve to build the overall story and lore, plus clue us in on whats been going on with the other characters we’ve met along the way in some form…and likely more so than has been done before, possibly finshing the whole overarching story up. (Like Blizzard has been doing with Diablo and Warcraft)
But, even if it doesn’t, the line we get from Typhon at the end (coupled with the line from the Eridian in TPS ending) clues us in that there is MUCH more to come, be it in upcoming DLC or in BL4
Thats just my opinion though.