While there is plenty to lament about how the service turned out, it's easy to overlook just how unprecedentedly fantastic it is, even in its current state.
The first Virtual Console games hit the Wii Shop Channel in North America on November 19, 2006 – the console's release date. It was likely a desperate move on Nintendo's part, an overture to the "core" audience following Nintendo in the past, when everything else about the Wii was a risky attempt to engage people who didn't care about video games, an attempt Nintendo did not yet know would succeed.
Twelve games were available that first day, including Mario Bros., The Legend of Zelda, Super Mario 64, and Sonic the Hedgehog, representing the NES, SNES, Genesis, and Nintendo 64 systems. Two days later, Turbografx-16 games Bomberman '93 and Bonk's Adventure joined the lineup. Eventually, the list of supported systems would grow to include Turbografx-16 CD-ROM, Sega Master System, Commodore 64, Neo Geo, and arcade, though none of these platforms (with the exception of the Neo Geo) had anywhere near comprehensive Virtual Console catalogs.
In June 2007, Nintendo celebrated the arrival of the 100th game on the Wii Virtual Console, less than seven months after the launch of the classic game download service. The game chosen for this milestone was Zelda 2: The Adventure of Link. The 200th game came out after another seven months (it was either Harvest Moon or Lords of Thunder, which were released simultaneously). It took all the way to May 2009 for the 300th game to arrive. Nintendo, noticing the milestone after seemingly whiffing with number 200, released The Legend of Zelda: Majora's Mask to mark the occasion.
Now, at the end of 2012, the Virtual Console stands at 402 games, meaning it took over three years to add the last 100, versus the seven months it took in the early days. In fact, only 22 games have been added to the lineup in the whole of 2012, including just one NES game (Double Dragon II). Twelve games by Data East and Irem were actually removed from the Virtual Console this year.
Other stumbles include the lack of portability. It's a bit crushing to have to buy NES games again on 3DS as they become available; and while you can play Wii VC games on Wii U (through a separate Wii Menu), Nintendo has only referred to a separate "Wii U Virtual Console" going forward, which is very likely going to be a different service with a different selection. Worse still, Wii Virtual Console games, like all Nintendo downloads, are tied to a console rather than to an account, and require the intercession of Nintendo customer service should your console die.
And it's not a Virtual Console retrospective without the obligatory "Earthbound isn't available" complaint.
But too much time has been spent dwelling over the incomplete collection, slow releases, and precarious ownership scheme. The Virtual Console changed the world of video games, at least a little. Since the beginning of the service, downloadable retro games have been made available on PSN, Xbox 360, PC, Mac, and even mobile platforms, and I have no doubt we would see many fewer retro re-releases without the Virtual Console. The service taught publishers that there is a market for emulated games, that it's potentially worth the hassle of obtaining the rights and re-certifying their back catalogues with ratings boards.
The change wasn't as dramatic as it could have been. Even post-Virtual Console, nobody else is going for as comprehensive an approach, opting instead for curated collections of bona fide classics. The closest exception is Sony's PSOne Classics, with its hearteningly random assortment of licensed Disney games and fishing sims, but even that covers just one console's output. There's really nothing like the Virtual Console in terms of breadth, no other place to discover retro games you might not even have heard about.
I don't know what the Wii U Virtual Console will be like, but I hope for a worthy successor, however futile that hope may be.