First, I don't think its necessarily accurate to say that COM and CHM students take most of the same classes. Definitely not most, 2nd year curriculums are completely different - CHM goes off into PBL and COM goes into systems. Even in the first year, COM and CHM students only take 2-3 classes per semester with each other max. All clinical stuff is done separately (doctor patient relationship for COM, and the equivalent type of class for CHM, etc.). And for this coming class of 2016, COM and CHM students will not be taking any class together anymore - everything will be completely separate.
In regards to the course load at COM, yeah anatomy in the summer made the first semester MUCH easier and sort of a breeze. Its not like that anymore. They restructured the curriculum completely. The semester after the summer and after have much more of a course load. COM students will be pretty much completing all the classes needed during summer/fall semester needed to start systems in January of first year. The current curriculum that they have been using don't start systems until 2nd year. This year MSUCOM is going to be a killer 1st year.... much more fast paced -- but the advantage is that we finish our classes earlier before boards and have more time to study for COMLEX.
The classes taken are all the same, it's just about the pace. This curriculum change was made because originally when this current curriculum was set like 15+ years ago board scores weren't as important as they were now -- so with this change comes an extra month or so to study for boards. So now it's about 6-7 weeks, whereas before they literally finished their last semester sometime in late May giving them 2-3 weeks to study.