Full Wii History
The Nintendo Wii's history and development started with the original codename for the console, "Revolution", being invented. Motion controller and software development occurred after that; Nintendo collaborated with different companies for different aspects of the console and the controllers. Development was concluding with bugfixes and overall improvement for the final release of the console.
Shortly after the release of the GameCube, Nintendo instates the blue ocean strategy and starts coming up with random new console ideas; we don't know exactly what they came up with during this time, but it's likely that motion controllers were already a big part of it, since Nintendo had been experimenting with the idea since the N64 days and Wiimote-like motion controllers for the GC marked "V-09 Sample" had been sent out to studios like Factor 5 and EA circa 2000. (See Pre-Wiimote Protos)
In 2003, the "Revolution" codename was announced, implying that the console will be "revolutionary"; this could either be just a general reference to whatever idea they had at the time, or, somewhat more likely, a specific reference to the motion controller technology (which at this point was likely in early development stages); the GyroPod was made around this time, indicating Nintendo's interest in actually developing motion controller technology; ideas from the DS (then transitioning from Iris to Nitro) were also considered for the Wii around this time, including the dual screen concept.
Motion controller development really gets off the ground, as a whole host of prototypes are made including those weird frisbee and GC controller prototypes you've probably seen from that photo (Pre-Wiimote Protos); this is all for GameCube still in terms of controller development, but the Wii hardware development also starts up around this time. Early development on the CPU/GPU and overall chipset design including the Starlet begins, boot0 is also probably written at some point during this year. Towards the end of this year the "wand" controller shape is considered; overall, this year symbolizes a lot of experimentation and playing around with the controller idea, so a lot of prototypes were made and scrapped; all software testing for them being presumably done on GC devkits, as the Wii at this point had no SDK or libraries and was still in very primitive hardware development stages. By the end of this year we likely had an early, wand shaped Wiimote and Nunchuk, and probably some kind of very early Wii board with the first Broadway and IOP (Starlet) revisions.
Software development for the Wii starts, controller development matures and (mostly-) finalizes, and the first Wii-related things are given to third-party devs. The VC service is likely conceptualized very early in this year or maybe last year, as Nintendo expands their online plans to the rapidly developing Wii. At E3 2005 Nintendo shows off the empty prototype Wii shell case (E3 2005 Revolution Case), but no actual hardware is shown; GCs are even used to run demos, as at this point development on the Wii's SDK has just begun, with a few GC things imported over to a Wii development tree but little new stuff yet. Nintendo mostly (some SDK drivers still use it) stops using the term "NNGC" at some point in this year. Nintendo mainly focuses this year on finalizing the Wii's hardware, both console and controller; the controller looks pretty different from final at this point but has the same basic design and is being distributed to third parties starting July 2005 as a GameCube peripheral until the Wii devkits/SDK are ready in 2006. The classic controller is also invented during this year, as a controller shell which the Wiimote would fit into. As the year progresses much more effort is put into the software development in the Wii, particularly in the realm of wireless stuff; the VC service is rapidly worked on with a Shop Channel prototype being made with BroadOn, as well as early channel/menu development, although at this point everything is in pretty early prototype stages, it does exist and most of the early prototypes of channels/the menu discussed in the Iwata Asks interviews are probably from later in this year. The controller in its wired version is mostly finalized by the end of the year with most work being focused on the still incomplete wireless version as well as getting the devkits and SDK ready for third-party release. By the end of this year, the Wii is probably close hardware-wise to final, although a few tweaks were most likely made between then and when the hardware was finalized in August 2006.
This is the big year where stuff goes from its prototype form to being ready for final release, as well as the Wii being fully opened to third party devs. This can be seen in both the console, controller, and software; the console is shown in its final physical form at E3 2006 this year and its hardware is finalized in August 2006 (as evidenced by release of the NDEV 2.1 as the final version NDEV), and the Wii's SDK as well as NDEVs are finally released to developers in March of this year. The controller goes through a lot of minor changes this year, including the infamous "pause/arrow" plus/minus button design (Dev Tool v4) and the round DPD (sensor bar lens), although the controller and Nunchuk retain the same shape that they did at the end of 2005.
The software most likely transitions into resembling final at this point; the TurboGrafx is added to VC in March of this year indicating constant active development on VC and by extension most likely the Shop Channel as well. As the Mii Channel was stated in the Iwata Asks to be one of the last channel additions, and it was revealed to exist at E3 2006, this most likely indicates that channels were being finalized around the time of E3 2006 as well, with everything between the Startup Disc Menu and final release of the Wii menu and channels most likely being minor bugfix type revisions. This is reflected in the start of system configuration library development at the start of this year, as well as a system configuration menu being given to developers around the middle of the year. "Formalities" for production like factory discs and 0002 are most likely made towards the end closer to system release, although much of it is copied from the GameCube anyways.
Libraries and the SDK are finalized as the release date for the system draws near, and by October 2006 the system and software are completely ready for final launch, with August-September most likely being minor software bug fixing. While IOS certainly existed in 2005 due to the existence of the Starlet, and likely in some early prototype form in 2004 as well, 2006 is the first year where we have information about its development, with IOS3/0, IOS4, and IOS12 existing earlier in the year with IOS9 being developed more towards August. DVD support is also scrapped in this year, likely circa or before E3 as it is not mentioned at E3. Overall, this year from start-E3 is a lot of finalization of stuff prototyped in 2005, with the rest of the year being a lot of bugfixing and finishing up for final release.