While I can't really comment on MIM Charvels, I can tell you that I own a few US made Charvels as well as a few custom Suhr Moderns and a Standard and those guitars are quite light, but I wouldn't say they "feel cheap" in the wood.

Some wood is more dense, others less... it's more dependent of where the cut of wood is coming from... old growth, new growth, where on the tree the cut came from, by the base, or up high, the particular tree... etc...

My USA ProMod is on the light side of medium and is a tank. Very sturdy feeling.

I don't equate weight with quality. Plenty of cheap plywood boat anchors out there that are NOT good guitars

Acoustically, I have played an MIM that had that cheap sounding noise. That noise that almost makes you think that the neck is hollow and the truss rod is just rattling in there.
But when plugged in, it was no different than my others.

I have an EVH Striped Strat body that is MIM. It is quite light and doesn't feel as "substantial" as my Charvel MIJs, but it is right up there with them for sound. MIM is no joke these days! My first MIM guitar was a 2003 Telecaster Standard, which was very good other than needing upgraded pickups. The MIMs being produced today are perfectly fine as-is. They've come a long way!