I have just finished BS4; I really liked it. It feels much more like BS1, though it still has its faults.
I agree with the ending being rushed; but thats the same issue in BS2 and BS3; only BS1 nailed the ending for me. Also 4 has alot of plot holes, and conversations towards the end of the game that don't make much sense/parts of the game that aren't clear. I have a feeling they had to rush certain elements to get the game finished; so it has some good puzzles at the end but some wierd situations
Spoiler:Such as the tramp appearing and disappearing; though that was funny. Also the priest Mark and the mafia guy Spallaci; no explanation as to how they know each other nor why on earth they are going to help each other from now on. Also that turkish investigator just reappearing and shooting whats-her-face. All elements that could have been developed more OR just cut. Why not just make Whats-her-face-maria an evil cow? Not this bizzarre "oh I slept with you george and suddenly regret being evil" stuff.
Either way, just like BS2, and BS3 this game needed an Epilogue to round the story off. At the very least a conversation between Nico and George. An epilogue could be to see him at the funeral of whats-her-face, comforted by nico and some dialogue to explain what they did with the Ark, and how they escaped the crypt without being shot by that group of nutty priests.