I do not put a lot of value in watching the water, because it just means the bevel is flat on the stone. But it does not tell you if the whole bevel is flat, or if the bevels are meeting fully.
Yes, it can be an indicator, as can the feel or sound, but why not look at it and remove all doubt. Keep it simple, as said do the small things first and be systematic in your approach. Systematic equals repeatable results.
Look at the bevels from the side, for even stria pattern, (and no deep stria reaching the edge) across the whole bevel from heel to toe and especially at the edge, are you honing to the edge. Then look straight down on the edge with light and magnification. If you see any shinny reflection, the bevels are not meeting fully. This take just seconds to do.
More importantly, if the razor did not shave well, there is more going on. Find out what that is. Is it a honing or stropping issue?