Yes I have dimmable LEDs and are using an approved switch. Doesn't work for incandescents either...

What you're proposing is fine (other than the fact that it is most likely technically illegal for you to do this not being licensed). Depending on whether this is just a switch loop, you may also be able to make the change at the receptacle. Did he check to see if the receptacle is split where one of the two sockets is switched and one is not?

I'm not saying that they didn't screw up. And I'm not saying that a jaggedly cut switch plate is proper. There is a better solution, but there might not be a totally great solution. I'm just saying that it might actually be impossible to move the box to a more appropriate place. For instance, if there is a big wide structural post right in the spot where you think the box should go. At this point, it isn't practical to tear down the house and redesign it and reframe it. So it's time to make the best of a bad situation So your options might be to leave it where it is with a switch plate that is better cut. Or maybe move it over two feet to the other side of whatever is preventing them from putting the switch in the proper place. Which is better? Maybe there are some other options, but the 'ideal' might not be possible. It's also possible that the electrician is just lazy and incompetent and there's nothing blocking the proper placement. Keep pushing until you get some real solutions and explanations of why something can't be done.

If a wall was dark or a heavily saturated color, I'd consider matching it: outlet/switch/wall plate. Otherwise, if the wall plates were not light almond, I'd replace them. If they were, I'd do nothing as I don't see a reason to draw attention to them.