I think the main thing with the Wii and DS userbase is just to not treat them differently than the other userbases. Like long time Nintendo users, PS2 userbase, and PS360 userbase, when they buy a system they are looking to buy games. They know they need the software to use the hardware, or they found it out when they bought it. Like most mainstream gamers, decisions are made in store. Only other influencing factors are word of mouth. Meaning, they are going to look for a game that sounds like something they'd enjoy or something they'd find fun.
But let's not take them for idiots. Like the rest of us, sometimes we make bad decisions. In the early case of 2007 and 2008, a lot of them picked up games they found to be like Mario Party or Wii Sports. They enjoyed them and wanted more. Gamers on all consoles do it. You wouldn't know how many times a day I get asked do you have any titles like "Uncharted, Modern Warfare, Halo, Gears, etc". But just like any other customer, they know if they have bought a product they didn't like. For instance, more than likely when Carnival Games or Deca Sports were bought, they were building off the hype from Nintendo quality games in similar genres. Some might have liked the game, but I'm sure there were lots of them disappointed in comparison to the Nintendo games they bought.
These gamers aren't stupid though. They aren't going to buy that brand again. They are going to see Deca Sports 2 and not buy it which is why that game has less than a fourth of the sales of the first or Carnival Games: Mini Golf has a 3rd of the sales. This is what happened on the Wii and DS as you started to see more and more 3rd party offerings start to, well, bomb. They had destroyed their brand earlier in the lifecycles with bad games and that hurt their brand appeal. These gamers stopped buying them and went back to the brands they knew where good, or the Nintendo brands in this case. Or they went by word of mouth games, or the "better" 3rd party offerings.
The thing about mainstream gamers, is they have different tastes than us. They are going to want sports games, hunting games, family games, "active" games, movie based games, etc. But that doesn't mean they don't know a good product from a bad product, especially if they have Nintendo continuously showing them what a good product is. And after they see the bad product once, they aren't going to get fooled a second time. This is one of the main reasons the whole "shovelware" period on the Wii and DS is dying and could be dead by the end of the year. That along with losing in the competition for shelf space.
So I find this to be a good notion that we should really think better of these mainstream gamers on all systems because they are just like us. They want to find a game they will enjoy. They are going to have different tastes, and different opinions of quality, but like us they know the difference between an attempt at a good game and "shovelware" and they showed that for Wii and DS sequels of many of those games. And luckily do to the large amounts of these gamers on consoles, if word of mouth spreads well, they can turn games that might have been medium-sized hits to big successes for the companies (Scribblenauts for example).
