I think if Nintendo wins you won't see a 400-600 dollar console launch next round....or the next round will not start for a bit longer allowing Sony and Microsoft time to gather the Higher tech at lower prices. A longer than 4 year console generation could force Nintendo to make a new system first. Allowing PS3 or 360 a 6-7 year console generation where they could catch up or pass Wii toward the end of the generation. More console gaming will be catered to family and in house than online
If Microsoft wins the next console launches will be 400-600. We will see a new "generation" of consoles a little faster than if Nintendo wins (Nintendo will have to decide to go with more expensive hardware or be a value console that caters to the masses) We will see a big step in trying to Synch your home PC to your console. online gaming will need to be embraced by Nintendo.
If Sony wins the next consoles will probly cost around 500-600. This will be a short generation as Microsoft will be first to market with a new system. Online gaming will be big for the next generation with a very in depth online community. The very Few Exclusive game will be a huge topic for the Next generation.
All that being said I don't think winning the console race in a generation is going to change anything all that much. I mean the X-box was in no way close to the PS2 in sales numbers, but Sony did notice that gamers did enjoy online play. Microsoft saw how much RPG's were a factor in the success of the PS2. The result =360 will be online and have more quanity RPG's than before and Sony will get thier RPG's and also incorparate online gaming. It doesn't take a console selling at #1 to get things to change...I am sure at least sony will be incorparating some Severe Motion sensing with the New Eye toy. There should be no Cons to any system offering up what people like.
EDIT:The only Con i see is that if the Wii does win and Microsoft and Sony focus thier sights on Nintendo instaed of each other Nintendo might be in trouble.(Sony is losing as much money on selling a PS3 at launch then it costs to make a Wii) So what iI am sying is Sony and Microsoft have so much money coming in from other places the could make a Console Comparable to Nintendos and sell it at next to nothing (if they were to go the non high tech route)
