Changing all xymatrix diagrams to tikzcd

[favonia]

I learned from @UlrikBuchholtz that this is something people want to do.

[DanGrayson]

Is there some advantage to be had from doing so?

[favonia]

@DanGrayson Can't speak for @UlrikBuchholtz, but I believe the xy package can produce ugly long arrows and for subtle fine-tuning it's much easier to just use the more powerful tikz.

[favonia]

@UlrikBuchholtz Is your plan to use tikz-cd or directly tikz? Personally the matrix mode of tikz is good enough for me, but maybe you have other things in your mind. My first cut will probably not be perfectly aligned, either.