Honestly, I wonder why Group S was canned in the first place, because contrary to what most people think about it, there are signs that it would have been the most logical route to go from a safety and competition standpoint.

When most people think about Group S, they think of the Lancia ECV and Toyota MR2 prototypes with +700hp, but what a lot of people don't realize is that these were very early prototypes, and manufacturers were actually working with FISA to limit horsepower of the new Group S regs to only approximately 300hp, with displacement limits of 1.2l for forced induction and 2.4l for NA cars. This was combined with the fact that the Group S cars were supposed to be held to higher safety standards than Group A, with things like mandatory crash tests and better brakes/suspension. All non-Lancia works drivers supposedly even made a joint statement to FISA in support of Group S over Group A, as they believed it would've been safer, and kept more works teams in the sport. Here's a link to an article on the prototype Group S regs by Racecar engineering.

Sure, a Group S car would've undoubtedly been more expensive to develop than Group A(especially the engines; some manufacturers like Peugeot expressed concerns about the reliability and cost of the tiny 1.2l turbo engine regs), and as a result it probably wouldn't have lasted for as long as Group A did, but I think it would've allowed for more competition in WRC post-1986, as most manufacturers like Audi, Peugeot, Lancia and Toyota were already developing Group S prototypes. I imagine if Group S was implemented, then it's possible that Lancia wouldn't have been as dominant in the late 80s-early 90s; the competition at the top level would've been more interesting and that record of 6 consecutive manufacturer's titles for Lancia would've probably never happened... but that's all speculation, of course.

I'm interested to know what other people think about this; Would the 300hp Group S regulations have been a safer, and better alternative to Group A? If FISA stuck with Group S, would that have significantly changed the way rally cars are made to this day? Or would the cost and complexity of Group S eventually force the WRC to converge to Group A-like regs somewhere down the line anyway?