I think a bit of a false correlation was made here in the first place, namely that because there is a perception that DTF considers the band's epics to be their best songs, that we naturally gravitate towards long songs. The problem that exists here is two fold; one, not everyone here thinks that, and two, Dream Theater works in a genre where, generally, long songs happen a lot. Simple math will make it likelier for a list of DT songs to feature long songs since the band tends to work in a range between 6-13 minutes in general. And again, there's a bit of "this is what this board thinks" not the actual truth. The wider consensus for what is best from bands is a lot different than this place. For example, the broader consensus with Pink Floyd is that either The Wall or Dark Side of the Moon are their best albums, and neither album has a song over 8 minutes long.
While I gravitate towards bands that do long songs well, song length isn't the sole determining factor for what songs I like best.