I agree with a lot of your thoughts here. First and foremost, we did need Rogers. He was the most stable, centerpiece of this bullpen. Without him, there are a lot of unknowns to sort through.
I think the offense on paper took a step backward, but it is nowhere near as bad as what we're seeing.
I still expect them to be a decent run-producing group. but I don't necessarily have confidence in all the same names as you.
I fully trust Buxton, Correa, Arraez and Polanco.
I feel we can count on Sano and Sanchez to hit for power and a very low batting averages. Kepler will hit for a similarly low batting average with fewer strikeouts and fewer home runs. He'll surely pull a lot of double play balls into the shift. I won't lose any sleep if they move on from him. His greatest asset is his ability to fill in as an average fielding CF.
To my eye, Kiriloff and Larnach are 2 flips of the same coin. One or both will likely turn out to be productive this season. Jeffers isn't an offensive asset. Urshela? meh. I like the glove. Gordon? no thanks. I think Astudillo would've been a much better fit as bench depth now that we have one poor hitting cather and a second poor fielding catcher at DH, and he's much more reliable for a tough at-bat as a pinch hitter.