You have a point, but on the other hand when the cv consists of only terrible fan-fiction or dating sim work (this new writer) and/or you say in interviews that your aim with Tyranny is to "reach the great reactivity of The Wolf Among Us" and your favourite game and inspiration is fucking Fallout 3 (Starks) things are not exactly promising.
Also, Ziets' first work with Obsidian was Mask of the Betrayer, which is to this day their game with the best writing, Avellone's first game was Torment, Gonzalez's first Obsidian title was New Vegas, and even if we look at Sawyer (although he's not a writer) his first game was Icewind Dale, which is not a masterpiece but a good game at least. You could already see some talent in their first works (well, more than "some talent" for Ziets and MCA especially), none of them started with writing Kills-in-Shadows and then went on to write the likes of Dak'kon, Morte, Kaelyn the Dove, Ravel, Kreia, Myrkul, Okku, etc.
Ziets first game at Obsidian was Neverwinter Nights 2, not Mask of the Betrayer.
Avellone worked on multiple games at Interplay before Torment. Fallout 2 and Descent to Undermountain to name a few.
John Gonzales was hired as a Lead Writer. Kirsch, Starks or their latest addition... nope. They've started as junior writers or writers, not as lead writers. He had one game under his belt as a story director and thus had actual experience for that position.
You need to look at the games these people worked on as well and what amount of creative freedom those said games give them. With Mask of the Betrayer it is obvious the writers were allowed to write amazing and way different than your normal fantasy crpg companions due to the setting alone, yet hardly anyone praises the companions in NWN2. I can't even remember a single one in that game.
Same goes for Torment, freedom to go crazy and to explore outside your normal fantasy companions.
Even a great writer can't do miracles if the setting and Project Director are there to trip them at every point which is why I want to see how they fare under different project director and on a different setting. I'm not saying Tyranny's writing was all bad, there were definately some quality writing there as well and I didn't find the writing all that bad to begin with. Then again I haven't played the game with all of the companions..
Demand for quality writers has also gone up since the early 2010's and Obsidian isn't in a position where they can just point at a project of theirs and get a great lead writer with the IP alone. Who wouldn't want to work on a Fallout game after Fallout 3 was a massive hit?