Currently, half the episodes of a show I am watching have a pre-intro scene, and half do not. So a setting to start only from after the intro would not work for this situation.
For a lot of anime, there is often: Show, credits, post-credits scene, next-episode preview. And even then, some episodes of the same anime DON’T have a post credits scene, while having it in others. So skipping to the end at the first credit marker would not be a good thing to do here too.
Believe me, I’d like this feature. Having an option to enable “Skip everything up to and including intro” and “Skip everything from first credits marker to end” would be nice, but would definitely have to be on a per show level. I’m not against it, but it’d be so much work for all my shows that I doubt I’d go to the effort to check any of my shows to enable it. Having the option, for people like you that are confident that it’d work for a particular show, sure, why not?
Now, if we had a nice GUI interface to be able to manually set or change intro/credit markers ourselves so we could manually include previously-on/next-time-on in the default markers, I MIGHT do that.
I do agree to have an option to auto-skip intros/credits. There is a fairly popular feature request to allow an auto-skip. It’s so popular that there have been multiple feature requests for it, all linked together (look at the linked posts 
).
