If there aren't any signs of previous problems and the pump is only on after a storm, I certainly wouldn't bother with that. Maybe have a backup system if your pump isn't water powered.

Did they indicate why they wanted to make it deeper/wider? I would only do that if there is a valid reason.

When I added a sump pit to my basement, I intentionally didn't go any deeper than I had to. My thinking was, once the water table receeds (I only get it when the table is perched) I want the pit to be dry as soon as possible. The deeper it is, the more it has to receed before it's dry.

Do you have an exterior or interior perimeter drain? If so, the pit only needs to be big enough to handle the size of the pump. When it's running your draining all the volume of the perimeter drain system, not just the sump pit itself.

Even if you don't have a perimeter drain, I wouldn't enlarge the pit unless I had a reason to....especially not to the tune of 2k.