Sony: They either half-ass everything and then patch them up to get it into a good state, I.E. PS3 Online, Home, OS features whilst being behind the ball or they get caught up in features and technology and to this day they seem to talk more about the technology behind their games than their games themselves.

To fix: Experience first, technology follows and not the other way around and they should plan better and invest where it counts.

Nintendo: If their gamers upstream, will it be to their console? Their greatest weakness is that they are caught up in their own self affirming beliefs about what the world wants. Its the Apple paradigm, they may get their first but theres a chance the other console makers will reap what they have sown longer term.

Microsoft: There seems to have been a die off, they seemed to have had a plan at the start of the generation but they haven't seemed to execute that great in the middle of this console generation. They need to think of ways to keep the overall excitement level up around their consoles because at present we're just waiting for Natal it seems. They need to learn how to sustain momentum better and to take advantage of winning situations. I think they should have been more aggressive than they were when they had the advantage even if it cost them another half billion to do it.

S: Being the hardware giant they are. Expecting others to accommodate themselves to the hardware they push; developers, etc. Making powerful hardware but not being able to forecast consumer interest in them. Building upon established formulas but never creating their own big thing.

M: Being the software giant they are. Releasing a faulty hardware. Having ugly hardware. Releasing expensive add-ons that feel like afterthoughts. Charging for a service, while working really well, that's free on other platforms. Focusing on non-gaming software more and more.

N: Being Nintendo. Never being able to satisfy everyone. Having the nostalgic fans indecisive about old franchises. Having new fans that want the next big thing ASAP. Being ridiculed by critics and those who don't have interest in their products for simply existing.

How is that a weakness when tons of people would still rather pay them for it than get it for free from Sony?

It's a perception thing.  Why is the Xbox the only platform charging for online play?  It turns off consumers and prevents consoles from being sold.

Does it? Im sure they have plenty of market research to back them up and its something which could be changed with a flick of a switch essentially.

Nintendo:
Fix online maybe a two tier system for different age groups? But remain free. Do what they are doing. Buy more studios and employees for next gen dev. Cater to third parties more. Make tech difference smaller so that excuse doesn't exist, allow us to watch DVDs on the Wii a simple software update will do, come on. Drop price to USD 99 by the summer of next year. Pokemon MMO/any MMO on Wii or PC, imagine SSBB like MMO. More connectivity between handheld and Wii. Do something crazy next gen with console able to output 1080p. Bundle both Wii Sports and Motion+ in a Wii. Advertise! New IP not related to Miis.

Sony:
Continue advancing the online while keeping it free. Drop price to USD 200. Include HD cables in system. Main thing to correct would be to anaylize what went wrong this gen and do not repeat the same mistakes and focus now on making the hardware next gen the best it could possibly be, additionally figure out the PSP situation.

Microsoft:
Same as Sony figure out what went right this gen and capitalize on that next additionally make better hardware in the beginning. Also main and largest complaint I say is make online free. Not having free online I would say is the one reason why I refuse to buy a 360, I am not willing to pay extra to use all the features of a game. I would not mind having advertisments on loading screens online. Also along with other people eluded either buy more studios/create more of your own or continue to make sure to hold onto solid third party support.

Research can't change the market.  You can offer filtered water in the middle of the desert for $12.50 a bottle and still suffer if piss flavored water is free right next door.

What market research have you done exactly? They have stuck to these guns for a while now, over 6 years IIRC that online be charged for. If they don't believe its a weakness then why ought we believe its a weakness? They have had about 200 opportunities to change it to a non charge model. At worst it is a weakness but the revenue gained outweighs that weakness and makes it an overall positive for them. 

Fine, I'm wrong. I concede to you.

Nintendo: lack of will to create good new franchises and make them last;
Sony: incredibly stupid arrogance and unique "copy machine" feature;
Microsoft: their thought they're the kings on video games as they are on computers...