Lets look at other games that have had sequels, not related to the original game... Red Dead Revolver -> Red Dead Redemption. Thats an example of a great game that got MORE AMAZING. But, then you have to look at the other sequel games... L4D->L4D2. ouch... Or even, I'll go so low as to say, Halo-> Halo2, heck yes! But, Halo2->Halo3, ugh, why Bungie!?
Whether it's necessary or not is irrelevant; they are always going to make a new generation while there is still an audience for the game and a potential for moneymaking.
Nintendo isn't as bad, but when you go from a pretty good thing, having to make a sequel out of it, just because they need to make money, the game will tend to suffer from it. Look at Metroid! Great game series, simple, fun, engaging. Prime came out, and it was a TOTALLY different spin on the series mechanics. Lots of fans backed out. With Pokemon, I fear the same, not with the massive amounts of newcomers, but with the Graphics. You put 3D in Pokemon, and peoples heads are going to be spinning. Thats not the only thing, aside from connectivity with DPPtHGSS, and the sudden superfluity of the Pokewalker, the "Crossing Bridges that are Diagonal" are some of the things that worry me about this series.
I'll be honest. I don't feel excited at all about this game. The new Pokemon look last minute and mixed up from previous creations. I seriously think this will be a dissapointment, I apologize to anyone who thinks it is promising. I mean, the graphics have improved. It's just that, I don't think making another region/game is even nessecery.
Honestly, people, all we can do is hope that GF will surprise us. When a game has this much hype, and this huge of a fan base, we can either conclude that, "This game is gonna suck," or, "Wow, they really know what they're doing up there at Nintendo, we should just give them a chance."
If you're tired of Pokemon, thats understandable. 15 years of changing and evolving (no pun intended) can wear a person down. I've gone through my Pokemon hating phases myself. But, when you're in the store, and you see Pokemon characters that you've never seen before on a big poster, and the game sitting there in the case, for a low price of 34.99, you'll think... "Ah, why not. Lets give those guys up there at Nintendo a chance."
:)
I was also excited at the possibility of a light type, but I think I'll be badly disappointed at this too, and Reshiram and Zekrom will turn out to be Ice/Dragon and Electric/Dragon like the rumors...
Anything but that type combo... I don't see what's so icy of electrifying about their looks...
Even Steel/Dragon would have suited Zekrom just fine... But no.
btw, I don't know if you've seen the new CoroCoro scans, but Reshiram and Zekrom's types ARE confirmed.
Zekrom-Dragon/Electric
Reshiram-Dragon/Fire