The answer depends on what kind of comparison have to be shown on the figure. If we want to show differences between genes, it is good to make Z-score by samples (force each sample to have zero mean and standard deviation=1). If we want to show differences between samples, it is good to make Z-score by genes (force each gene to have zero mean and standard deviation=1). Original heat-map contains both information. So the phrase that it is "less informative" does not suite here. But redundant information makes useful information hard to see. Z-scoring does not reduce dimensionality, but throw away information about means and standard deviations in rows or columns (genes or samples). Think what information and what comparison you are discussing in paper and make proper Z-scoring if some information is redundant, else if all is useful - leave the original heat-map and explain this point to your reviewer.

The answer depends on what kind of comparison have to be shown on the figure. If we want to show differences between genes, it is good to make Z-score by samples (force each sample to have zero mean and standard deviation=1). If we want to show differences between samples, it is good to make Z-score by genes (force each gene to have zero mean and standard deviation=1). Original heat-map contains both information. So the phrase that it is "less informative" does not suit here. But redundant information makes useful information hard to see. Z-scoring does not reduce dimensionality, but throw away information about means and standard deviations in rows or columns (genes or samples). Think what information and what comparison you are discussing in paper and make proper Z-scoring if some information is redundant, else if all is useful - leave the original heat-map and explain this point to your reviewer.