It actually isn't as sharp with many modern emulsions as D-76 because of the lack of solvency not releasing edge sharpness enhancing iodide from the emulsions - and the larger visual granularity destroys fine detail resolution faster. A lot of what people describe as higher 'sharpness' is actually stronger granularity (possibly just below the threshold of perception) in relatively small enlargements. The lack of solvency also may be part of why Rodinal seems somewhat less likely to shoulder highlights with many emulsions. If you like Rodinal's 'look', the old 'Universal' type of film/ paper devs (at appropriate dilution) can do the same sort of thing, but in slightly different directions.