It's essential to use a "modern" grip of some type, from most rec up to pro.
I'm defining "modern" as where you hold the racket like a mountain bike handle, rather than a steak knife. That's enough for a massive improvement.
Bad grips are probably a major factor in the demise of the 1hbh.
So people need to be educated about the nature of grips, but this requires better terminology.
Current terminology is ambiguous and confusing, and the internet search results unfortunately promote the Eastern "steak knife" grip rather than the grip pros actually use. Unfortunately, even reputable sites like Fuzzy Yellow Balls makes this mistake.
Defining grip purely by index knuckle is ridiculous. Consider that Dimitrov's continental grip and Wawrinka's mild Eastern grip actually play more "extreme" than a rec player's Eastern Steak Knife grip.
And using an Extreme Eastern steak knife grip isn't much better. It's mostly about the heelpad. See the pics in this recent thread:
Index knuckle combined with heelpad positioning would be ideal, and I can't think of a more marketable workaround aside from replacing the heelpad with the little knuckle, which is easier to see.
So ultimately, this is a battle of definitions.