I agree with your overall point, but Elementary is as much as a remake of Sherlock as Sherlock is a remake of Sherlock Holmes in the 22nd Century. Its distinct universe is one reason why, for its comparative lack of cinematic and dramatic merit, it's still around after three seasons.

Gracepoint, on the other hand, may have well have a shot for shot remake of Broadchurch. I could only tolerate two episodes, but I heard they tried to change the ending in an attempt to give people a reason to watch, but failed and cancelled after one season. Sticking to the same plot too closely will doom any remake.

British remakes can succeed, and there is occasionally a good reason to make them. For example, where changing the setting changes the story. Take House of Cards for example. The original had no chance in the US. Differences in the political mechanisms of London and Washington means the story had to change. Plus, Americans audiences generally aren't exposed to enough British politics to have the grounding needed to fully appreciate it. There's nothing so different about American and British detective-work to warrant this in Luther's case.

Where a show lacks emphasis on an overarching plot there can be more potential for a remake to succeed. Take The Office, or Shameless. These shows are only loosely based on their UK counterparts, and with the talent they've employed they've been able to distinguish themselves in their own right.

This is a road the IT crowd could have taken, but they fell into the trap of simply attempting to clone the original. Maybe lacking the confidence to attempt to improve upon it.

Luther and Utopia are two of my favorite shows in recent years but they both have tight plots, which do not rely heavily on setting, and indispensable characters. While I'm skeptical of both, at least Utopia has David Fincher on board. He's proven his hand, with remakes of House of Cards and Girl with the Dragon Tattoo. Compared to the broadcast networks, HBO has a very consistent track record of quality shows. Luther doesn't seem to have anything similar going for it, so I really hope it's scrapped.