That would work in an ideal world but DO schools are so large and so bloated now that it doesn't work that way. Maybe in the past it worked that way but it doesn't anymore because of just how many more students there are now.
Just to give one example, Rocky Vista has only 1 small general surgery program in its OPTI. With the logic that you presented above, they would place very very few students in that specialty because they wouldn't be rotating in home programs, etc. etc. But, on the contrary, they have placed more DO students in sub-specialty programs per capita than any other DO school. If you look at NYIT's ortho residencies, for example, you will probably see 1 NYIT student for every 4 outside student. Another example, I don't think Western's ortho program in nor cal has taken a Western grad in the past 2 years, maybe more despite Western students having a rotation preference.
Take it from a second year who is literally IN the process right now. Things are changing. Program directors have much less of an association with schools and many of these OPTI's are losing their leverage over hospitals after the merger. Many OPTI's weren't even granted institutional accreditation (including NYITCOM's OPTI) and the whole idea of why we are even spending money funding OPTIs in a post-merger world is in debate now. A PD (DO or MD) would take a DO student from Creutzfeldt-Jakob COM in Anchorage, Alaska if he had higher board scores and a stronger resume than the PCOM grad because, with the merger, he knows his job is on the line if his program doesn't get a 100% pass on the national licencing exams. In the past, rotations had a huge impact but, again, there are too too many students now and now that programs are shrinking in size because of the new ACGME rules, program pass rates are a much bigger worry in PD's minds than if they recruit students from "Old 5" schools or their home students.
OP: You really don't know what things are going to look like in 4 years. Just go to the school you seem to like more in the area you think you would enjoy more. No one knows for a fact what the GME climate will look like in 4 years but what we do now is that things are changing and, whatever the changes are, it's too early for you to worry about them now.