It doesn't matter much until you become probably at least 1800 USCF because you are going to screw up the middlegame somewhere anyway. What good is a slight advantage when you hang a pawn or make a huge positional blunder? I like to study openings also but real chess is the middlegame. For the sake of this forum question: I play the Colle some and it won't be found in master chess so it must be overated among club players. It is popular with books,etc.
Note: I guess Fisher did not know much about chess since he played the KID and the Sicilian almost exclusively.
Real chess is the Endgame.
Ask Capablanca.
Fine, I really didn't mean overrated. It's just that some people play the Sicilian so much that it has 30 moves of theory before you can actually play a chess game. On the other hand, the Advance French is REALLY overrated.