Models are spiky. In some narrow domains (cybersecurity, for instance) it will be a generation ahead. On the other hand a lot of people don't see a measurable difference between Opus ~4.5 and 4.6/7/8, because Anthropic taught it how to do some hard stuff better, but they didn't give it better taste or make it produce cleaner solutions to simpler problems.
Fable is very much an incremental development over Opus, and even more incremental when properly compared to its existing counterparts GPT-Pro and Gemini Deep Research.
I have a design for a really complex software I want to build and there were gaps I knew of in the design. Opus couldn’t identify them but Fable did. I’m just talking about it reviewing the design, not coding. But yeah, it’s insanely expensive. It does spin off sub agents so I suspect it might be cheaper if you had it create a bunch of plan files and then pointed deepseek at this plan files or something like that
Can you write a more specific question? I think the meaning of the comment is clear enough, but maybe you’re asking for more specifics? Ironically I can not understand what you are asking for with such a generic comment.