I think the arrangement your designer suggests should will be good, but with any lights the amount of lightbulb kelvins will determine light output. Consider getting the brightest possible for bulbs (3000-4000) and have dimmer switches for both overhead and sconce lighting. Not sure of your bath layout but you could have 2 recessed lights above vanities and another two that would be behind you somewhat when standing there, would help remove shadows.

I never bother with dimmers in a bathroom I usualy do 2 switches one for the task lighting above the vanity and one for the overhead pot lights I just leave the task light off when I want to have a bit more softness while I have a bath. I like 4000K lEDs in both batjhrooms and kitchens they have no yellow undertone like 3000K does and IMO both these spaces need to be lit like operating rooms ( I amjoking a bit) since both require good lighting to perform tasks .