Phrased that way, how is 5E, or 1E, any different? There is a consistent system of rules, with room for a shared understanding of the odds and impact.
I don't think 5e and 1e are all that different, in that respect. They both have areas where the rules are solid, and you play "GM ad hoc ruling" outside those areas.
There may be a small difference in overall tone - 1e already has lots of "save or die" type things, so failure cold be understood to mean rocks fall and everyone dies.