Yes... but many mods have DLLs + don't release its source code... so you'd basically be rewriting whole mods...
Not necessarily rewriting them, but it may take some time to get sources extracted back, compiling and working in a newer solution, particularly when you get iterators IL code to write back to clean, working c#.
It also depends on migration scenarios: for some mods, it's tough work (things changed in vanilla code since last mod working alpha), for others it can be straightforward.