This is a question about the aesthetics of mathematical typesetting, as well as a technical question about LaTeX.
I'm writing a lot of expressions like this:
(\log\frac{p_{i\to j}}{p_{j\to i}}
in a display math environment.)
This looks odd to me, because of the very large gap between the fraction line and the denominator, compared with quite a small gap between the line and the numerator.
I realise that in some sense that gap needs to be there in order to accommodate taller characters like 'A' or 'b', but since there are no such letters in my expression it seems like it might look better if the spacing were different.
So my questions are (with roughly equal priority):
Should I be messing with this? Am I right in thinking the expression looks unbalanced, or should I just trust the algorithm's designer (presumably Knuth) to have made the right decision about how to typeset this?
If I should change it, what should change exactly? Should the line be lower, or should the denominator and/or numerator be higher up?
If changing it isn't a terrible idea, what is the best way to affect such a change?
I believe this is not a duplicate of How to vertically center the fraction line?, since that question is about how the spacing relates to the font, rather than to the actual characters used in the numerator and denominator.
\log\frac{p(i\to j)}{p(j\to i)}
, so you don't have subscripts in the fraction? This might be easier to read, unless it violates some notation convention important in your discipline.