Well 5e is more or less a basic version of 3.5/d20 system, so there are lots of things that no longer make sense after you gut the rulebook. 3.5 had skill ranks. Clerics started with a bunch of ranks at 1st level and then would continue to buy ranks in religion every level, and would be much better at related knowledge checks than an unranked 18 Int wizard in no time. Knowledge skills relying on Int makes sense. Having a skill system that no longer takes into account character life choices and experiences, does not. I'd really like to see the solution to these problems be to add back rules rather than further dumb things down by making every class centred around a single stat. Despite its flaws, 3.5 had a lot that is sorely missed.