Do NOT worry about 3rd and 4th year rotations. For now concentrate on getting through years one and two (and step one). But, to ease your minds, TCOM has plentiful and quality rotations. EVERY school sends some students to away sites in the 3rd year. IF you get sent, the school provides housing while you are there. In the 4th year, you don't get 'sent' anywhere. You set up your own rotations where you want them - in Fort Worth, New York, Africa, etc. The increase in DO schools will, hopefully, increase the number of osteopathic residencies, but has nothing to do with "options" for core rotations.
In the 3rd year you will have the *option* of moving to Corpus Christi for all of the core rotations and you can stay there for some or all of your 4th year electives.
Still not convinced? Check out the match list in the osteopathic forum. It is a great list, because TCOM trains great doctors.