prune ornamental cherry ; water sprouts?
Old trees not pruned in years. Many "water sprouts?"
If your question is about removing "water sprouts", yes you should, but within reason and with selective judgement, case by case, cut by cut. Thinning to reduce overcrowded branch structure and poorly placed water sprout growth is beneficial.
Removing more than 25% of the canopy at one time is not advisable. Leaving selected well-placed water spouts and shaping them to become part of the branch structure can be considered.