>>45212717Diamond & Pearl were revolutionary for their time, but aged like milk. Their Elite 4 is awful, but Platinum fixed their shortcomings and is the definitive way to experience Sinnoh. Sinnoh has this "difficulty" attached to it. Difficulty being the strange way you traverse the region. You criss-cross across Mt. Coronet several times in different ways. "Difficulty" because of that interview regarding little kids getting lost in Mt. Coronet, which was the beginning of the end.
The other Gen4 games: HeartGold & SoulSilver were beloved by everyone and are probably the fan favorite games of the series. Gen4 has the most spinoff games of an generation and some of them boast connectivity with mainline games.
The only issue I have with Gen4 is the long damage animations during battle (watching a Blissey lose HP takes eons), and the long animation during saving (saving a lot of data). The actual time it took for these to finish may not actually be as long as they feel, so there is some psychology involved in the time spent watching these animations.
Gen5 is my favorite gen, but I can see why people like Gen4.