Just look at longitude. 100 degrees pretty much splits the country. So ‘midwest’ would be between 90 and 110 degrees.
East, less than 90 degrees, west more than 110 degrees.
It’s simple.
Okay, now that this is (not) settled, explain how the Midwest is in the USA, but the Mideast is a whole hemisphere away, in Asia.
We also have a Far East… Where is Far West?
Buffalo Wild Wings.
Their jerk wings are awesome, I can live with that.
Just add Hudson Bay to that (roughly the northern 1/3 of Minnesota, northeastern half of North Dakota, and a sliver of South Dakota and Montana) and we’re golden.
Huh. Never noticed that.
For such a flat area, the Great Lakes region sure has a lot of watersheds.
Yeah, the only reason I know that is I once read about the Red River, being one of the few north-flowing rivers in North America, causing problems during the spring melt - evidently, when conditions are right, the southern, warmer part of the drainage (the higher part) can start to melt before the northern area, so the water gets backed-up behind the ice, and floods.
I’m from the east side of Cleveland, my mother has strong western PA influences, and I never heard that in my life. For reference, the waterway in question was Doan Brook just north of the Cultural Gardens.
I grew up code-switching. At home, my college-educated mother never spoke anything but standard educated English (with a few Pennsylvanian dialectal expressions learned from her mother). Outside, I learned the local vernacular of the other kids, but with that one exception, we always said creek. It may be that the reach of “crick” that far north is spotty.
Where do we put the Great Divide Basin and other anomolies?
But the Great Lakes (naturally) drain into the Atlantic, no?
True, but as I noted above, that’s an annoying geographic anomaly.
Besides, if we can consider the Gulf a body of water separate from the Atlantic, why not the lakes, too? It’s all arbitrary in the end.
But that, again runs into sociohistorically/socioeconomically/sociocultural issues, longitude 100 was traditionally the marker for the “West” in the sense of the drier lands that could not broadly sustain high density farming.
Fight the good fight, but ISTM any attempt at geolocational prescriptivist redefining of “Midwest” that puts parts of Texas or Montana or Mississippi in it is doomed IMO.
I could imagine favoring a version of your suggestion, but acknowledge the Great Lakes’ drainage to the Atlantic, and replace West/Midwest/East with Pacific/Mississippian/Atlantic.
Still leaves the question of what to do with a state that straddles a divide - like Colorado.
Strikes me as curious that anyone would advocate for CO to be Midwestern. They have mountains on their license plates, for crying out loud, and one of their pro teams is the Rockies. 
WRT TN, instead of East I would have East and SE, divided at the Mason Dixon line. Then I would somehow divide SW and West. Somewhere in the middle of that would be the MW.
Maryland would be southeast? Puh-leeze, MD is Mid-Atlantic!
SW should be easy, have Adams/Onís take over from Mason/Dixon. Used to be Mexico? You’re Southwest. Note that STILL messes up Colorado.
The South only exists in the east. The western south isn’t South, it’s Southwest. I suspect the South is mostly defined by BBQ. Maybe slavery, but mostly BBQ. /s
For the sake of convenience, let’s just say that any state that features a divide, shall be counted as a state on the oceanic side of the divide. That means that Montana, Wyoming, Colorado and New Mexico are all Western states, while Pennsylvania, New York and Vermont are all Eastern states.
Never mind, corrected on edit.
When you’re right, you’re right.