Sure, it would change the color, but isn't the color already altered due to the increased density of the wort? By adding water, you'd be diluting the SRM back to what you originally expected.
By having a higher extraction yield, you will suffer a slight loss in alpha acid isomerization (likely not all that noticeable with an 8%+/- efficiency difference). You'll be under-pitching your yeast if you do not account for the higher OG, so you'll likely suffer the consequences of under-pitching (ester formation, yeast stress, longer lag time, etc). Those are two of the most common concerns with higher than expected efficiency if it is not diluted back to what you expect.
I frequently account for higher efficiency by adding cold, filtered water at the end of the boil. This accomplishes two things. Primarily, it gets my OG back on track, and secondarily, it assists with chilling the wort. You could of course add the water pre-boil to get it back on track, and not suffer a loss in hop utilization, I just choose not to since I tend to go overboard on the hops anyways when I'm brewing a hop-forward beer. The consequences of adding water back into an overly efficient wort to get it back on track are minimal, if there are any at all. The sugars are dissolved in the solution, so as water is added, the sugars will blend with the fresh water all the same. If you choose not to dilute the wort, just be sure to pitch more yeast, as under-pitching can carry some very noticeable consequences.