God NO! I always found it really horrible that 10s and 25s had separate gear, so you absolutely HAD to do both. I think flex raiding is a good solution. "Forcing" people into 25s is not answer, even if it happens to be somebodies personal preference. I prefer 10 mans and I'm happy knowing I can fully ignore 25 man raiding. (I also like not having to stress about 2 modes worth of achievements when I go back to old content for fun runs)