>>19925207Except that there are equivalents to most of those. Following Pokemon was a pointless addition to Yellow that returned in Heart Gold and Soul Silver for fun. There are things such as the Battle Subway and Battle Maison that replace the Battle Frontier (or, arguably, just the Battle Tower).
DPPt technically had secret bases, because the Underground was set up in much the same way. The only real difference was that you could only see friends when they were nearby in real life, and you could not battle with them down there.
Seasons were most likely removed because, as neat as they are, they're a frustrating mechanic that can limit gameplay by requiring you to wait a month to get certain items or Pokemon (or Pokemon forms), and most people just end up changing their DS clock anyway.
