Here's my take on drywall vs skim vs full update.
Skimcoat
Skim coating over the plaster that is already cracking would not be a good idea. Even if you use a harder more durable mud or plaster, it will still most likely crack because of the age of your house, and the fact that your walls are already cracking (and will probably continue to do so). The other down side is the sanding mess.
I recently bought a condo that had nasty texture as well on the walls which I wanted to get rid of. I decided for the first room that I would use a heavy 60 grit paper to remove as much of the larger chunky texture as I could. I then skim coated with drywall mud to smooth out the walls. It took several coats to get perfectly smooth, and a whole lot of cleaning afterward. But, in my case, I know my drywall is sound and not cracking underneath, so I could reliable coat without having to worry about patching too much in the future.
Drywall
Using a thin drywall layer over the top may be a quicker and cheaper solution. This will eliminate the cracking issues and will give you as smooth a wall as you like, with little mess in comparison to skim coating the entire wall.
I would still use a 60 grit paper or paint scraper (if it will cut through your texture) and knock down as much of the heavy texture to allow the drywall to sit closer to the surface. This will help eliminate waviness in the wall where the texture might be outrageous (like it was in my house), and allow you to use a thinner drywall.
A possible major downside to this is electrical boxes? Maybe someone with more electrical knowledge can speak whether adding 1/2 inch thickness to a wall would cause issues with the electrical boxes being set further in? If so, again, I would sand and use 1/4 inch.
Full Update
If I was going to be living in this house for the rest of my life, I would consider a full update, especially if I was already going to be making changes to wiring.
This solution is costly, time consuming, and messsssy! But, the upside is that you can fix/update your electrical to be safer, and more suitable to modern appliances. You can also add low voltage through the house which (if you're a tech nerd like me) may be a nice plus. This will also give you perfectly smooth walls that won't crack and a feeling that your not hiding a mess in your walls.
Hope this is helpful!
Consider using a paintable latex caulk. Apply a very small amount then work it into the length of the crack with a finger. Wipe off all excess with a damp rag or sponge, then paint. It is a good method requiring no sanding. If your ceiling is painted with flat (no gloss) paint, as most are, you will not be able to see it when you are done.
Best Answer
Short answer is that it's probably fine. Just set it, patch, texture and paint.
More nuanced answer depends on where in the house it's in. If it's a bathroom or other high humidity zone, don't worry about it. (Generally, sheetrock is screwed these days, but it's common enough practice to tack sheets in place with a few nails. Nails aren't particularly rust-resistant.)
If it's below a bathroom or a roof that you might have cause to be suspicious about, then a bit of exploration might be in order. Look for stains nearby; touch the ceiling to see if you can find anything spongy or cooler than its surroundings.