For someone that's not as conservative, or a different view on the cycle, they might have a different opinion than me on all of this.2) Sponsor quality check: (takes about 45 minutes per deal)I believe that a great sponsor can take an average looking deal and make it great, and that in mediocre sponsor can take a fantastic looking deal and make it bad (especially if there is a severe recession).

I think the problem here is your lumping ALL syndicators, regardless of operational time and quality, into 1 big generalization. 

A quality deal you have control (under contract, seller only wants to work with you, etc.)3.) 

The allowed rent amount should be pegged to market rent, so it would only be way off if your unit is a way different quality or neighborhood compared to average. 

I really am a fan of RISD because it is high quality across DFW in general even relative to the big names in Collin county.

A lot of people will pay $1200/nt for 4 crappy budget motel 6 quality rooms at the All-Star resort rather than $175/nt for an 8br themed out mansion with a private pool, theater, and $30,000 arcade room.To answer your original question on investing over a long-term period, that is really this market's main strength. 

(Avoid managers who profit from repairs.)How do you screen prospective tenants?

Tell them that you are serious about running a quality STR and to have them call you at the first sign of problems.That will give them some peace of mind and have a way to get a hold of you instead of calling the cops.

Other factors such as the quality of the tenant, and location will also determine the value you can get.

Also the new owner has the advantage of screening their own tenants and signing leases at or above market rents.