The OP said he was 25, so he and his friends would have played in the early eras, going way back to RBY/GSC. Their thoughts would be on those generations instead, not RSE since they didn't play it. In general, people were turned off by a lot of things. For one, they couldn't trade in their lv 100 Typhlosion from Crystal. Another would be that this region's Pokemon had very different designs versus the current generations (at the time). Less people played at the time. So the nostalgia-crazy fans pretty much abolished this generation for being so different, but gradually warmed up to it.Overated in my opinion. Many people like you are always complaining why is this gen underated. Its also the time when many people stopped playing Pokemon, so whenever you say the word "Pokemon", their thoughts would be R/S/E.
Jellicent points in his post seem to say otherwise. So Contests, Battle Frontier, Double Battles, Weather, EVs/IVs, Two Teams, and Two Champs(in different games of course).I guess it is because really few points have been added to this gen. yes they have made a new story, pokemon and what not, but the features basically stayed the same. Nothing too revolutionary had been added, unlike Generation II and IV.