For me...I don't know the D/P/Pt trades were awful. I particularly only really liked the Buizel for a Chatot one, although Chatot wasn't particularly useful, it was great getting it early in the game compared to having to wait five gyms though and playing around with Chatter was great fun. <3
Although the Medicham for a Haunter trade was a major letdown :x. I honestly thought the Haunter would evolve and I was so pumped, I had badly wanted a Gengar for the longest time and then I receive a Haunter holding an Everstone, was really disappointed. XD;. Although I must say other trades like Finneon for a foreign Magikarp were quite interesting but overall D/P/Pt in-game trades could have been miles better. :P
And as for HG/SS I liked them! The French Pikachu was really cool and I thought they were all neat.