Personally, I wouldn't say it will necessarily send floods of applicants our way, but I do think that it will shunt some people in the direction of podiatry.
There are many people out there who more than anything else just want to be a "doctor". If we're talking the prototypical DO applicant here, then we can assume that their stats are already below the threshold for MD, DPT, and DDS/DMD schools even before the loss of grade replacement. After the loss of grade replacement, a number of potential applicants will no longer meet the threshold for DO school either. Out of applicants for the 2014 DO entering classes, 7,886 applicants had cGPAs between 3.20 and 3.59. With a drop in grade replacement most of these people would no longer be anywhere near the DO school matriculant cGPA average of about 3.52. Plus in that cycle there were an additional 3,896 applicants with cGPAs below 3.20. How many of these students would be pushed out of the acceptable range nobody could say, but just because of the huge difference in number of applicants to DO schools vs DPM schools, even only 1% of these students getting shunted towards podiatry would increase the podiatry applicant pool by 10-15%.
I am certain people will be affected, the only question is how many people will be and where will they go to. The only options for them would be to continue going to school (e.g., Master's program) to try to get their GPAs up but there are already a number of people in my class who have settled for whatever reason (e.g., age, impatience) and just went into podiatry instead, so clearly not everyone is willing to stick it out for another two years just to maybe get into a DO school with the potential of having to settle in the end anyway.
The only decent options left to such a person would realistically be podiatry, optometry, or pharmacy—since again MD, DPT, DDS/DMD, and now DO would all be out of their GPA range. Pharmacy is not like being a "doctor" and so I would assume people who were set on being a "doctor" would settle for podiatry or optometry before pharmacy school. Stats for optometry school and podiatry school students are very similar, though proportionally fewer people apply to optometry school. Basically anybody just shy of applying to DO school would have a fair shot at either podiatry or optometry school—slightly better shot at optometry. For those really wanting to be a "doctor" I think they'll gravitate towards podiatry. For the others I think it'll probably be split pretty well between the two since they each have their pros and cons—primarily that optometry is less school but podiatry has a larger scope of practice and higher earning potential.
If I were a prepod right now, I would just keep in mind that the possibility that there may be increased competition next cycle is there and I'd do what I could to bolster my application so as to be safe rather than potentially sorry. It is a factor that has never existed up to this point and there's no way to predict what will happen next. I wouldn't blow it out of proportion, but I also wouldn't blow it off.
At least that's my thought process.