Not necessarily, here's why. Although I can agree with you in principle all wiring connections in J-boxes come loose over time and as they do the resistance increases and so does the electric bill. Especially with aluminum wiring.
Ceiling lights that are enclosed contain the heat and feed it to the ceiling and thus to the wiring connections. (With incandescent lights) I have had shorter than expected life on any bulbs outside of LED.
Anyhow, I have to replace the entire fixture because I got sick and tired of the problems. When I removed the fixture, I found all the associated wiring from the fixture, cracked, and pieces laying about. The wire nuts all showed signs of heat, and the last couple inches of the house wiring were discolored and very brittle. These were your typical 4x4 boxes, not the deep ones, and there was very little "spare" wiring, so I had to be careful and clip the wired where it was all soft insulation, and then reconnect them to the new fixtures. That is what drove me to checking out the possibility of LED wiring, with remote transformers. Since if this happens again then someone is going to have to crawl the attic and replace the wiring anyhow.
If the J-boxes weren't right next to the fixture you could shoot it with a temp gun, or infrared camera looking for signs of heat, if so it needs to be repaired. Most systems when they fail in the J box just with open up or short against the box. Chandeliers are very prone to this as is any type of ceiling fixtures.
So what I am saying is that it is a real possibility if you are going to run new wire anyhow.
Now if the wiring has enough slack in it, then all fixtures could use the original house wiring with low resistance to 12 volt lighting and then all that needs to be done is cut the wiring someplace that is serviceable, and install a transformer between the light switch and the fixtures. That would be the simple way.
In my MH all I had to do was twist out the old bulbs and insert the LED's. A bit pricey, but it was worth it for the extra days in the boonies without burning gas for the generator.