I personally think it's great that there are all these new dragon types, even multiple pure dragon, since there are barely any dragon types overall. Of the non-legendaries, 3 of them are dragon/flying and 2 are dragon/ground. Before this game, Kingdra was the only unique typed non-legendary dragon, as the other 6 are legendaries (and Rayquaza is yet again dragon/flying, making 4 total) I'm counting only the fully evolved forms here, since that's all that matters.
So only counting the final forms in Gen 5, there are 2 pure dragons, dragon/dark, dragon/electric, dragon/fire, and dragon/ice. Only 3 of them are legendary, and they are all unique types not in previous gens. Dragon was always the sparest type anyways, so I think this is a great step, and I don't see how anyone can complain about it, though they really should have done a dragon/bug IMO.
Also more ghost types and ice types are needed, thankfully Gen 5 is adding more of them as well, as well as GOOD bug combos, instead of the horrible bug/flying, bug/poison, and bug/grass, even though those last 2 are in this game again -.-
And snowcone, I'm glad the water types are sparse this time. There are WAAAAAAY too many water types in the other gens, as well as grass.