Except that modders have fixed some of these issues easily and paradox could even copy the code if the wanted to.If Paradox did not care about its customers, then why would they let @Rounoush's comment remain in view on Paradox's own discussion board?
They do read the boards and they do censor comments (I should know), but not comments like that.
Give Paradox some credit. You don't have to like their games (though I do), but making and maintaining these games cannot be as easy as it looks. Sometimes bugs that look trivial to fix (a) aren't, or (b) are not believed by the developers to be bugs.
Paradox lets one play an old version if one is dissatisfied with the new. This is a concession on their part.
Personally, I would recommend buying the DLCs.
Incidentally, I literally posted in the bug forum the code to fix poland keeping their elective monarchy reform after being PUed but it wasnt included in 1.30.4.