> The only time when GM will definitely analyze more lines than an amateur is in a highly tactical position
Those critical moments are a big part of the difference between a GM and a good club player though. If a GM was somehow handicapped to not calculate such tactics, I think lesser players would be able to draw games against GMs much more often.
I agree that GMs can avoid calculation in many positions (e.g. openings as you said), but the value of broader and deeper calculation is still huge in chess.
Those critical moments are a big part of the difference between a GM and a good club player though. If a GM was somehow handicapped to not calculate such tactics, I think lesser players would be able to draw games against GMs much more often.
I agree that GMs can avoid calculation in many positions (e.g. openings as you said), but the value of broader and deeper calculation is still huge in chess.