To me, ranking systems is an idea that has pretty much become extinct since the GameCube era. How does one rank systems nowadays? By their impact on the market? By sales? By other functionality? By controller? By color?
Most of the time, it is based on the library for that system. But does that mean one should include or exclude those other factors? Look how many people have to give different criteria as to how they are making their rankings. The more common or accepted method is probably the one Ian outlines by software library and by the elimination of previously released titles as mentioned here:
I'm not counting VC releases as part of the Wii unless that was it's first way to play the game in your region (ie: in North America you need to own a Wii to play Sin & Punishment). Backwards compatibility doesn't count either. You buy a console for the new games it provides.
Yet why is it so necessary to be strict? Why should it matter what was released when? Because then Wii or Wii U would be the best console? Great. That's how it should be. A newer console should be better than the last one.
In the past, console rankings made sense especially when there was so much software that was tied to one system. But in the past decade, so much of the software from the early generation systems has become more easily available or re-released on newer systems that it's rendered them more and more obsolete. I haven't turned on my NES in maybe 6 or 7 years. I haven't played my SNES in possibly 4 years and that's most likely the same with my N64. Part of that is because I've played most of the games I own for those systems pretty thoroughly. Part of it is because there are so many new games to play. However, being able to just play them all on one system or in a re-released form has also made a big difference in my not using them anymore.
In the past, when I could only play Super Metroid, Kirby Superstar, or Super Mario RPG: Legend of the Seven Stars on my SNES, then the system had a more concrete advantage when comparing it to a system like the GameCube. It's still just ranking games but because those games were tied to one system, it made the system important. But now that I can or could play those games on the Wii or Wii U, it erodes the whole idea of ranking consoles based on their software.
EarthBound was an SNES release but I'll be playing it on my Wii U and that is how I'll first experience it. (Besides briefly trying it on my PC from downloading a ROM of it.) Punch Out and Super Punch Out were both experienced on the Wii for me. So does that mean I should rank them on the Wii console side or that counts as points for the NES and SNES side? Does it matter? Ian mentions Sin and Punishment 64 as being a Wii Title since that was the first way North Americans could really experience it. So, is release date what really matters? Should it be?
If a person plays EarthBound for the first time on the Wii U, shouldn't it count as a Wii U title? If I play Super Mario World on the Wii U, isn't that Wii U software since it is on the system and I've chosen to play it with that console instead of my SNES? I used to buy older games for my SNES and N64 until the Wii came out. After it came out, if there were games for those systems I wanted still, I just got them off the Virtual Console. It didn't make sense for me to try and track down the old physical copies of these games at a higher cost when I could play the same thing at a cheaper cost and more convenient set-up. What happens when a game is re-made and re-released with improvements over the original? Does that make Wind Waker a GC title or a Wii U title?
When it comes to Nintendo consoles, as far as I'm concerned, the only ones you need to still own are the 64 because of the Rare software mainly, the GameCube because most of it's library is still tied to that system and the Wii U since you can play all Wii games on the Wii U and it has the Wii shop all tied into that system also. With the virtual console and game companies re-releasing software most other consoles are rather obsolete. For handhelds, maybe the GBA depending on how that VC grows on the Wii U (although an older DS could play those GBA games as well) and a 3DS.
It is sad to say since I loved my SNES for a decade until the GameCube finally won me over about 9 years ago. But nowadays, when I look at a systems software, I ask what can it give me that I can't get already. Bubsy 2 doesn't really cut it. I may encourage someone to try a bunch of SNES classics but I wouldn't really tell them to get an SNES since most of the games I'd recommend could be played on the Wii U. A ranking of consoles is really a ranking of where game design is/was at. As more and more games get re-released or remade and offered on more and more different consoles, trying to tie down software to a certain console or restrict where it "truly belongs to" seems to be an outdated method to praise or criticise a game console in an increasingly irrelevant and obsolete competition based solely on furthering an individual's opinions and agenda.
In other words, business as usual at NWR! 
It is something I find myself less and less concerned with the more time passes.