Obsidian will always be a good studio but i have played everything with their name on it, except PoE2(which everyone agrees is better than PoE1) but simply look at their track record since NV(which they built in 18 months). A lot of big names have left or moved on, thats life and why Obsidian is just a name. today.
The only big names I can think of that left are Gonzalez (works on Horizon) and Avellone (freelancer). The studio was made for "retirement". Most of the RPG veterans that were popular in the 2000s are at the studio.
Josh Sawyer, the main guy behind New Vegas, still works at Obsidian (as showcased by this thread). Tim Cain and Boyarsky, the guys behind Fallout 1, work at Obsidian. The big names are still there.
I truly believe that Obsidian was struggling these last 10 years. New Vegas was supposed to be a relief, but their bonus was not given (the 84 metacritic situation). Alpha Protocol didn't land well (funds were cut during development according to rumors). It was a really hard time pitching their games when they had such a record of commercial failure following them around (low sales and related stuff).
Hopefully the Microsoft purchase helps them turn a new page.