R' Mayer Schiller is a fascinating individual who is Charedi but has taught for 25 years at MO high schools, and in many ways has a very MO hashkafa. Here is a very interesting essay about Torah im Derech Eretz and MO (I am quoting 1 very small piece here, it is worthwhile to read the whole thing).
The average lad in yeshiva/Hassidic world is clearly committed to halacha and resonably knowledgeable in Torah. The average Modern Orthodox boy lags far behind. There is simply no comparison between the 2 worlds when measured by any objective standard of Torah and mitzvos.
I know this is a painful truth. I wish it were not so as it argues strongly against the feasibility of Torah im Derech Eretz
I cannot escape the sense that a shitah that which assents to and embraces all of God's creation will produce a better talmid of greater shleimus in his service of Hashem.
This is the bottom line. MO while theoretically great (even superior as R' Schiller states) doesn't seem to really work for the masses. No one has found the formula to teach Torah im Derech Eretz while still maintaining that commitment that the UO have to Torah and mitzvos.