I have tweaked many an edge-lit set inside a Magnolia showroom. Not totally, completely dark, but not very bright either. These rooms are meant to emulate a "home" environment. Ones that I remember well were sets such as the Sony XBR10, Sony LX900, and Sharp LE920/925UN. To be sure, yes, turning the backlight down does indeed lessen the severity of clouding and flashlighting to sometimes, perhaps, even negligible levels. I have found, however, that it does not eliminate it completely, which I find maddening. I guess I'm one of the few people who actually love watching movies at night in a completely darkened room. In other words, this is when and how I do my most "critical" viewing. It is in this environment that full-array sets with local dimming excel.
Back when I was purchasing an LCD, I originally purchased a CCFL-backlit model, a Toshiba XV645. After I took it home and adjusted it accordingly, I found the picture great in the daytime, but disappointing at night - e.g. when watching movies in the dark. It was not so much that the black levels were not good or (relatively) deep, it was that the backlight was not uniform, even when the brightness was low. This is the problem that I have with edge-lit sets; it's not so much that they have poor black levels, because they certainly don't. It's because they simply aren't and can't be UNIFORM because all the light is coming from the edge. This is especially apparent in larger-sized panels, e.g. 55", 60" panels. Aside from higher potential light output and reduced cabinet depth, LED edge-lit models produce no real discernible performance advantage over the heavyweights of CCFL when they were still being produced - like the Samsung A850, B/C 750, Sony Z5100/XBR9. It's also seemed that with the introduction and domination of edge lit sets uniformity has gotten worse than old fluorescent-based sets. The real improved performance has always come from LED-backlit models, and one of the main benefits-aside from deeper blacks (which are definitely discernible to anyone planning on doing any remotely critical viewing) is near-perfect uniformity, which helps as panels get larger.
To address blooming - I have found that the amount of annoyance it presents is relative to your distance from the screen. The LG LX9500 looked horrible close up. When I sat down at a normal distance from the panel, the blooming was just about negligible. Most LCD-based TV sets are an exercise in compromise in one way or another, but reading these forums or reading reviews, a universally shared opinion is that backlit, LD LCDs offer the best performance and least compromise when compared to, say, a plasma.