admittedly there are times in HL2 where I go nuts, but that was part of the experience
HL2 coming out 6 years after HL1, then with episode1 2 years after that and episode 2 a year later in 2007 we are now again 6 years since the last installment.
I am looking forward to seeing how the story progresses, it is still the best quicksave smasher I have played, and while the originals may be dated the openness of Source and Steamworks gives modders/developers the freedom to port old levels and releases to newer incarnations of the engine, so if Source 2 kicks the same as Frostbite 2 then we are looking good
Of course it is not everyone's cup of tea, I have a few friends who don't like it and others that would do great harm to those that dare say anything against the franchise.
When Half Life 1 first came out it re-defined story based FPS games, doom and quake had pretty much just been a run and gun affair up to that point.
As others have mentioned, Half Life series has been copied to death.