I would have to say that it is not based entirely on the fact that the Glock trigger system has been around for a long, long time now. Add to that the fact that it has been field tested for 20+ years by individuals and police agencies all across world, and it should be obvious that the evidence suggests that it is not a dangerous arrangement.
If a light trigger concerns you, spend the 3 bucks and either install it yourself or take it to a Glock armorer (they are pretty easy to find) and spend the 5 or 10 bucks he charges you to put it in. I don't think it is particularly dangerous just because it's light, but it may be your just not comfortable shooting a light trigger. Heck, I am like that myself. Of course, I like my triggers to be crisp, and I certainly am no fan of 11 pound pulls, but for whatever reason I just have a hard time controlling a "light" trigger as I am finding out with my Bushmaster Varminter. In a pistol, I don't think you will ever find a trigger as light as that one is, but my point is that if you don't like it, you can fix it easily and cheaply.
Also, since there have been two responses to your question without the obligatory "buy a 1911", I feel like I should say something.
Buy a 1911.