There are a few plausible reasosn for the appearance of Denny's promos on Hampton Inn tables:
1. As a service to guests. Denny's may be open 24/7. Hampton food service will not be.
2. Co-ownership of both businesses.
3. Denny's pays a fee to the Hampton property.
These are all utterly free from irony.
The sentiment that Corporate standards force mediocrity has been explored in other threads (in which the good JDiver has posted). The argument - umm - lacks intellectual traction.
If one wants to explore the idea that Hampton standards demand no better than mediocrity for breakfast, go for it. Lots of HHonors FlyerTalkers have figured that out - and look for HGIs or Doubletrees at comparable price points.