Well, the tradeoff always seems to be between development speed and processing power. The more generic you make the code, the less well it will run. So flash is just weak and slow compared to what you can accomplish by delving into lower levels. This has changed a little over time with flash, but it's annoying to have to keep waiting for Adobe to stop dragging their feet on everything. I think people tend to hate on them because they aren't challenged by any other software platform in the niche they've carve out online, so flash progresses very slowly. I mean, they didn't even have 3D capabilities until a year or so ago, and they botched that pretty badly, IMHO...
As a counterpoint to what you said; if you build your own framework solidly, you only have to do it once, and you can update it yourself whenever something new comes along. The programmers you're jamming with just don't have their own framework, so it seems like flash is much faster because they're using one that's already made for them. Someone had to write the code at some point, though. The only real advantage flash has is that you'll be able to release it online for a wider audience. This is still a big enough plus that lots of people will use it (though, with lots of grumbling, hahaha).
Kenney
Yes, right on. Flash is an absolute dream if you need something done by the end of the day.