The wireless features of Pokemon Diamondand Pearl are definitely the most notable additions to the series. Being able to trade Pokemon via WiFi is just huge. Thanks to this feature, being able to "catch 'em all" isn't the Herculean task it once was. Sure it'll still take a lot of work (for those of us that don't wuss out and resort to a cheat device like Action Replay), but WiFi trading makes completing your Pokedex exponentially more achievable.
While trading with people you know via WiFi is certainly useful and appreciated, theGlobal Trade Station (GTS) is a true achievement... that's hampered by a banal feature set. Just in case you've been dozing off like a Snorlax, here's the skinny: GTS lets you trade Pokemon with people all over the world. You're allowed to offer up one Pokemon at a time, while shopping for countless Pokemon that are in your Pokedex. GTS is great, no doubt about it, but it's most definitely lacking. Here are some aspects of GTS that we wish were better.
Above: Pokemon Diamond and Pearl's Global Trade Station is a fine addition to the series that could have been so much more
1) Only Being Able to Trade for Pokemon You've "Seen" is Stupid - This is the most common and obvious complaint. You could be a Pokemon veteran that has spent hundreds of hours playing the previous games, but if you haven't seen a Bulbasaur during your adventures in Diamond or Pearl then there's no way you can trade for it. Bulbasaur could have been your favorite Pokemon for years. You could've seen it countless cartoons and movies. But because of this silly control, you can't ask for one. This is kind of dumb.
While we understand the need for a control, there surely must have been a better way. Being able to copy your Pokedex from the GBA games would have been a nice solution that rewarded players for all their hard work. Still, this isn't the biggest problem we have with GTS.
2) There are Not Nearly Enough Pokemon Details on GTS - While it's nice to be able to select the gender and level (in a very limited fashion) of the Pokemon you're looking for on GTS, it's not nearly enough - not by a long shot. You should definitely be able to sort Pokemon levels better than GTS allows you to. As it is you're allowed to select Pokemon level nine or under as well as ten and up, with the latter option increasing by increments of ten. If you're looking for a specific level Pokemon then you're pretty much SOL. Say you want aPalkia that's between level 47 and 55. There's no way to specifically search for one and you might miss out on the exact Palkia you want since you can only look for ones level 40 or higher and you'll be flooded by the current inventory.
For competitive players, it's worse. Being able to see the stats, nature, and moves of a Pokemon makes a huge difference. Being able to pluck a properly effort-value trained Charizard with an adamant nature and the Belly Drum/Flamethrower/Earthquake move set would save a competitive player lots of breeding time and possibly a valuable item (the TM26 used to teach Earthquake). A Charizard with this setup might be worth the extra Entei in your collection and would certainly be more valuable than a Charizard with a busted move set (we hate when people use moves like Rock Smash on really good Pokemon).
If you were able to see all the details of a Pokemon posted on GTS, none of this would be a problem.