Do you find Fable significantly better than Opus at avoiding-overengineering? All of my recent testing of Anthropic models seems like they're tuned-to-hell to (a) be much slower than they need to be (running tests over and over during the loop vs at the end, say, even if those tests take a few minutes a pop) and (b) doing exactly that sort of "built a lot of fancy enterprisey feature-adjacent 'stuff'" even before nailing the actual feature. Sol and Terra both have some of the latter but they seem to do the actual work a fair bit faster (this may be a usage-based-priority-tier/rate-limit thing though) which helps offset it.
I think the bigco folks saw all the "it wrote all this code but the tests didn't pass" or "it wrote the feature but it's super brittle" and tuned the newer model+harness combinations incredibly aggressively to try to turn a lazy prompt into "median Enterprise Architecture design suggestions" to bring up the baseline, but in a way that slows you down if you don't want that.
I'm not on big enough subscriptions to want to burn a lot time just evaluating Fable/Astra comparatively until they're cheaper, heh. I can steer any of the cheaper ones just fine anyway.