It's important to understand that the way things work in Japan is much different than many western countries. You can't apply the rules and common practices of America to what happens there. It's just so much different, legally and culturally.
What we do know is that there have been offers to buy Nikon and move the company out of Japan, relocating it to China, South Korea or Taiwan. The Japanese government wants Nikon to remain a Japanese company, and they are making an effort to prevent the iconic camera company from leaving.
That's where Fujifilm's "help" might come in. Fujifilm has returned from the brink of death to become a healthy, profitable and innovative company. They know how to turn things around and to thrive, not just survive. They can offer Nikon a good deal of direction and advice. And possibly some money. At this point no one knows.
The question is, what kind of direction should Fujifilm give to Nikon? How much influence, if any, will Fujifilm have over future Nikon products?
If I were Fujifilm, there are some things that I would suggest that Nikon do and not do. To be clear, these are my own ideas, and I have no affiliation with either company.
I would start off by designing some new full-frame DSLRs. Nikon had some success four or five years ago, but didn't follow that up with anything. Where's the D820? Where's the D760? Where's the D620?
Nikon shouldn't take the same design and slap a new decal on it. It's been too many years, and people are waiting for an upgrade--and wanting a good reason to upgrade. The new cameras need to be fresh and they need to have some advancements over previous models.
The bodies of the DSLRs should be modeled closely after vintage Nikon SLRs, like the Nikon F2 and the Nikon FE. Give the new cameras a retro shape. Make a statement, yet keep it classy. Nikon should include shutter speed and ISO dials on the bodies like Fujifilm does.
There should be five new full-frame cameras. One would be a 24-megapixel low-end model that is still feature-rich and would also be fairly small and lightweight. Make it the smallest and lightest full-frame DSLR out there, and make that a selling point. It also needs to be affordable, so make it one of the least-expensive full-frame options. This camera would be an excellent introduction to full-frame for someone coming from APS-C and would also make an excellent second body for someone who needs that.
The next camera would be a mid-level option with 36-megapixels. It needs to be a full-featured body with everything the pro would want. Basically, take the D810 and place it in a retro design and update all the bells and whistles to bring it to today's standards.
The third camera would be in the same body and have the same features as the 36-megapixel camera, but with a 46-megapixel sensor in it. For those wanting maximum resolution, this would be their model.
The fourth camera would share the same body as the previous two, but it would have a 16-megapixel sensor that would be optimized for speed and high-ISO (and it needs to be excellent at both). This would be the sports photographer's option. The entry-level camera should have 4K video, the others should have 6K or 8K.
The final full-frame camera would have a similar retro design, but it would be a 35mm film camera. Yes, a film camera! Film is making a comeback (to an extent), and for Fujifilm this could help with their film sales. It would be really fascinating if Nikon made a brand-new pro-level film camera, and it would certainly get a lot of publicity.
I know Nikon tried a retro-looking DSLR not very long ago that completely failed. The problem was that Nikon got everything wrong that they possibly could. Fujifilm seems to get a lot right with their designs, so perhaps they could help Nikon with this.
As far as APS-C DSLRs, I like the D3000 series a lot. These are very basic entry-level DSLRs, but they are small, lightweight, affordable and produce good image quality. They are easy to recommend for someone wanting their first better camera, and they are excellent as spare bodies. Nikon just needs to make it a little more enticing by including a few of the features from the D5000 series cameras (while still keeping the cost low).
Nikon should figure out which cameras sell better, the D5000 series or the D7000 series. Whichever one is more profitable, keep that camera and nix the other. If you keep the D5000 series, include some of the favorite features from the D7000 line. If it's the D7000 line that you keep, figure out a way to make it a little more affordable without compromising the features. In other words, kind of merge the two into one camera.
Why only two APS-C DSLRs? To keep costs low. Make two DSLRs that people will buy. Want something entry-level? You've got one choice. Want something more advanced? You've got one option. Fewer choices can be a good thing, just as long as they aren't missing key features.
Nikon should also make a compact fixed-lens APS-C camera. Fujifilm might not like competition for the X100 and X70 series, so perhaps it should have a different focal length (35mm, perhaps?). Make it look retro (maybe really retro, like a Leica II). Have it be a conversation piece. All three APS-C cameras would share the same 24-megapixel sensor.
If I were Fujifilm, I'd suggest against mirrorless. Why? Because if Nikon were to make a successful mirrorless camera, it could eat away at Fujifilm's market. I wouldn't offer any help in this category. However, if Nikon wanted to quickly get some quality mirrorless cameras on the market, they should buy Samsung's now-defunct NX line, and change the lens mount to Nikon DX.
I think Nikon should mostly scrap the pocket point-and-shoot genre. Sales of those types of cameras have plummeted thanks to cellphones. Have two options, one for entry level (auto-everything) and one for more advanced users (larger sensor, better lens and manual controls), and leave it at that. Don't waste a bunch of time and money on a dying category.
Where Nikon has an opportunity is in the cellphone market. Make an Android phone that has a zoom lens. It doesn't have to be crazy, but a cellphone with a 3 times or (even better) five times optical zoom would get people's attention. The biggest problem with cellphone cameras are that they're not particularly versatile. I think people would buy a cellphone with a zoom lens on it, especially if it had Nikon's label on it.
Another money-maker for Nikon is glass. A good in-demand lens will return significant profits. They should look at options for FX and DX where they aren't currently manufacturing a lens that people would buy. I know that for DX, for example, what is badly missing is a fast wide-angle option. Come up with four or five lenses to fill out what's missing. I definitely see some potential profits here.
Nikon should follow Fujifilm's blueprint, and that's to immediately cut what's causing the big loses, make products that consumers will get excited about, and diversify so that not all of the eggs are in one basket. Don't have too many of the same product. And make sure that your customer service is top-notch. Boom, Nikon's fixed.