I liked HG:L a lot actually, and I've completed it with Summoner, Guardian, Blademaster and Engineer. Every run was different, and loads of fun, as the classes are varied, but well balanced, and require different tactics to succeed. That aspect of the game is very similar to D2 actually, but without the massive machinery of Blizzard to support the game (and fund it), it failed to achieve as much as it should have. With Blizzards QA department in addition to their marketing crew, I'm sure things would've looked quite different.
Point is, the developers at Flagship were just as skilled when making HG:L as when making D2; they just didn't have the kind of support and what not they did at Blizzard (people seem to think the term "developer" means anyone working in the gaming idustry).
Anyhow, I'm sure SC2 is this years release (first campaign), and knowing Blizzard I'm also fairly sure it'll be a smash hit. Will it be as good as SC1 was back in the days? Probably better, but percieved as worse, due to the extreme expectations, and how the industry has developed since SC1 was released (as someone previously mentioned: SC1 is really lacking compared to some of the RTS games we've seen since then).
Edit: I should add that by complete I mean on the first difficulty. I did not max all these characters (level 50 is the max if I recall correctly - I think most of my characters are 40-ish). I just don't enjoy playing a game through more than once with the same character (which ultimately means the exact same gameplay, looks, feel etc of the character).