Great report, but you might want to think twice about playing up the "Guatemala is dangerous" angle. It simply isn't, any more than other countries with tourists, but it's that word-of-mouth that gets it... at the same time, you state that you wandered all across the country with highly visible valuables around your neck and were completely fine (as 99% of all visitors). You can't do that in a truly dangerous place.
You could have had a great time exploring the historical core of the city (Zona 1) and taking some great pictures around the central square, but you didn't because you had heard that it was dangerous... it's just a myth. If you'd stayed at a place like Hotel Spring or Hotel Seville instead of near the airport, you would've seen families, artists, musicians, couples, senior citizens etc. all strolling along la Sexta. You're certainly not the first to be convinced that the city was somehow teeming with peril, but keep it in mind for next time! Think about visiting Huehue and heading deeper into Quiche as well, possibly attending a town feria if at all possible... you'll get some unforgettable images.