My e-mail address was harvested years ago: I have to rely on spam filters anyway, so I don't really worry about publishing it in bug trackers.
Registration is a pain, I agree. However, on a project that I participate in (openMSX) we did decide to stop accepting anonymous bugs reports, since the majority of bug reports lacked essential information to be able to reproduce the bug. If there is no way to contact the user who filed the bug, the only thing a developer can do is close it as non-reproducible ("worksforme" in Bugzilla - a very poor choice of words in my opinion).
How well a project responds to bugs differs a lot per project and also per individual bug. Some are fixed years later, some within a day. Some are marked invalid even though they are valid, others are indeed invalid or are duplicates. The compiler projects (GCC, LLVM, Intel C++) have been relatively good with responding to my bug reports, so I will report new bugs to them when I find any. For some other projects, I don't bother anymore unless it's a data destroyer or security issue.