I've always gotten the feeling, at least back when I was a more regular BS reader, that Simmons never enjoyed the writing process.
He created tropes (quote columns, countdowns, rankings, etc.) to give himself structure. Creating structure from prose is hard work; work that he didn't like to do, and wasn't great at. Luckily those conceits were novel when he began, and they became part of his trademark style, so it worked out for him.
His columns were so long because he never edited himself; editing and crafting writing is hard work. Luckily, because nobody else in his field was writing that way, it seemed novel, and eventually became part of his trademark style, so it worked out for him.
Then, when he got big enough, he started to indulge what he was best at. This was smart on his part. Simmons values conversation and un-varnished reaction; that's why he podcasts (it's just capturing live, extemporaneous thought) so often and writes so much less frequently. It's why he likes to reconstruct me:/him: conversations and even whole minute-by-minute diaries in his writing. It's why, I suspect, he likes moving talented chips around at Grantland and letting them interact with sports and with each other, more than he likes writing himself. Bill's an observer and a reactor, not a writer. His greatest strengths (his work ethic, his sense of humor, his sense of timing, and his ability to spot talent) defined most of what he wrote, and they're the same things leading him away from writing.
That's why I don't really care to read his thoughts on the current Red Sox team, but I would probably listen to a podcast where he interviewed Johnny Gomes, or watch a 30-for-30 about the 2013 team ("More Days in October"), or read many of his hand-picked stable of writers' thoughts on the team. No ill will towards Simmons intended - the evolution makes sense. I just don't want to read a piece on the 2013 team that's a lame retread of his previous work, where he pretends he hasn't evolved.