I have no problem with it when it's a sub-genre. There are fans of this stuff just as there are fans of hentai. If stuff like Queen's Blade started coming out in droves, then it would be a problem. But, I still don't think the anime industry is at that point yet. Heck, the harem genre almost took over anime between 2001-2006. Yet in my years of collecting anime during that time, I somehow managed to avoid the brunt of the harem craze, which is now thankfully subsiding a bit.
Like I said before, with anime you simply have to know what you want. If you go around indiscriminately watching everything out there without some degree of research, you're never going to be satisfied. Sure, you'll find a hit every so often, but you wasted your time with the others because you had no idea what you were getting into. It's the Allen Iverson method. Shoot a bunch of shots and hope that 40% of them go inside the basket. Instead of doing that, exercise some shot selection! It's not like you have to spend hours researching titles either. You should pretty much know if you'll want to watch something or not just by looking at the back of the DVD case, or googling an anime title for a brief summary of it.
My thing is, nobody is FORCING people to watch Queen's Blade. Heck, people here shouldn't even KNOW about Queen's Blade yet, let alone seen an episode of it. If you can work that hard just to find a way to somehow watch it before it's on DVD, then you can do a little research on a show before you watch it.