For example, it's difficult to appease a situation if 1 tenant claims they're using less electric/gas than another. 

If either you or the investors are not highly experienced, this system is very very difficult to slow the first couple flips profitable. 

Build a solid foundation before taking a step up - each and every step of the way.There’s a way to scale recklessly and there is a way to scale safely.When OPM is involved safe is way better than reckless.Despite a life long career in RE, I scaled as followsBought a few duplexes for my own accountBought a fourplex for my own accountBought 12 units as a JV with some friendsSyndicated 43 unitsSyndicated 30 unitsBought another 12 units as a JVSyndicated 281 unitsThis was over a 3 or 4 year period.and so forth - now I am GP in close to 1000 units with $125M AUM.Even with all that, my sweet spot is 30 to 50 unit properties - they work best for my partners and I and more importantly our investors. 

Pot smell is notoriously difficult to get rid of. 

Financing can be expensive and difficult to find.  

Not trying to be difficult this is a serious question?

Not so difficult. 

getting cash flowing rentals in those states is certainly possible, but much, much more difficult than advertised. 

In my opinion, dealing directly with the seller for the first deal can be difficult.

You could have 10 of these, and they get progressively difficult.