Objective-C was by all accounts a nightmare to work with
I loved it. Loved it.
Some background: in the 90s I worked for a developer here in Toronto with a Mac and Win app. I wanted to work on the dev side but I had no formal training, and I found the barrier to entry to be too high for my interest level. To do anything useful, you had to learn the OS, the IDE, the language and the library, each of which was some level of dismal. For instance, the text editor widget on the Mac couldn't handle 32k, and the various libraries just called it. If you wanted to edit more text, well, have fun!
In 1998 Apple sent me a copy of OpenStep, or as they called it, Rhapsody Preview. After some install issues (lack of drivers, had to replace the CDROM drive with one it knew) I had my first real program running in a day. Real program.
Because unlike the Mac or Win of that era, the OS was the library, and the library was f'ng amazing. Text editor? How about one that fully supported Unicode, was limited only to 32-bit int in length, automatically paged data as needed (because that how the whole system worked), did complex layout like columns and flowed around graphics and such, and had a built-in spell checker. The entire library was like this, the base objects were super-powerful out of the box and tightly integrated with each other and the entire OS as a whole. I hate to use this word, but it had synergy that had to be used to understand.
Contrast with, say, Win + MFC... gebus. It was like Lisp Machine vs. PDP-8. .Net helped, and C# is better than Obj-C (I'd say it's my favorite language), but it was decades before .Net got close to OpenStep of the 90s, and even today its base objects still suck - why can't the get an array type right after 20 f'in years?! Every time I use it I end up wondering why some totally base object is missing some totally obvious feature, or why they have five objects to do the same thing, each with their own set of dumbness.
Obj-C was no worse than other languages, except perhaps in syntax (perhaps). It had two super-amazing advantages though. Extensions let you add code to existing compiled objects, so you could add spell checking to someone else's text editor for instance, and the handling of nil was wonderful.
Swift... well I like some things and don't like others. The whole class/struct thing they boast about is, to me, a crock. Yes, I know it's more efficient etc, but it really is much less flexible than just declaring a class and using it. I also hate hate hate putting the type after the declare,
int c=0 is simply easier to read than
var c:Int=0, and
int doSomething() is lightyears better than
func doSomething() -> Int. Bah! Swift also lost the wonderful nil handling, and I can't for the life of me see an upside - everyone just puts
! on everything.
Overall, yes, Swift is an improvement. But Obj-C was pretty great too. At least in the 90s. It collected a LOT of cruft when it moved to Mac/iOS, and much of that was ugly and just totally bolted-on. So early Obj-C and Swift were pretty similar in ease-of-use IMHO, while late Obj-C was indeed getting to be a real downer.