C# has the feature-bloat of C++, except with a garbage collector. (I wrote C# for 9 years and even when writing it 40 hours a week, I still had trouble keeping up with all the features that continually came out)
If you compared modern C# to C++03, then maybe (although even then I would argue that templates alone are more complicated still).
Not that I ever had this sentiment but even if so: why would you try to do that? Most new features are tiny enhancements you can live without and the big changes (generics, Linq) you cannot do without so you they are forced anyway. ‘Trouble’ sounds like you were actually bothered by it which seems a bit over the top?
The only problem I have with it is it is still really Windows only, hopefully that will improve with .Net Core 3.
Maybe you are talking WPF / Desktop only; there are other options for Mono but yes, there you would be right. However the trend is, unfortunately, toward browser interfaces (Electron etc) and those you can do on Linux/Mac already with .NET Core.
I wasn't thinking of Desktop although I would love to see something strong emerge there (other than Avalon).
Ah, curious what made you feel that. We ported massive code bases of ASP.NET and commandline tooling over to .NET Core since the 1 and had not many issues. It's a much better experience now but it never felt unfinished to me.
I have to admit that I have been writing software for a long time and one of the things I automatically do is abstract (not too far, just far enough) the underlying implementation of whatever I make/made. So our old ASP.NET code was very easy to port for that reason; I never use internals directly and still do not. For instance MVC looks more or less the same anywhere so I just use plain old C# classes as controllers so they can be reused by apps, other (non ASP.NET) frameworks, commandline, tests etc. It adds a thin layer below them so they work but it saves a lot of time and with the coming of .NET Core it proved smart once again.
I'm developing a C# application on Windows (netcore 2.1) and it deploys and runs on OSX without a glitch.
I've been writing games in C# that run on Windows, Linux, OSX, iOS, Android, Windows Phone, UWP, AppleTV, Nintendo Switch and more for years now.
Ironically, the most compatibility issues we had was with Windows Phone and UWP.