To answer the OP.
Straighter is greater if that's what the shot calls for.
Straighter is not greater if the outsides are unplayable because they're either too slick or too dry.
Bowling is about playing the lanes the way they should be played (as it suits one's particular game), whether it be from the twig, lofting the gutter cap, or anywhere in between.
In other words, whatever line is getting you to the pocket with a good angle of entry is the way to go (naturally, this requires one to be versatile, and just about all of the pros are, including WRW).
Walter has won several tourneys playing the outside line (perhaps the high majority of his wins), but he has also won quite a few playing more in on the lanes because he didn't have a good look outside of the track area.
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If it is to be, it is up to me.