ELT's are somewhat over rated. No one is required to have a 406Mhz ELT, the mandate only requres you to have a 121.5Mhz ELT which, by the regulatory body's own admission is COMPLETELY OBSOLETE.
MH370 mysteriously disappeared and because of that everyone is in an uproar because they weren't required to have an ELT but even if they had been required and even if it had worked the only difference now would be that we might know where it is. It wouldn't have prevented what happened from happening, all on board would still be dead.
I'm pretty sure that this incident is going to result in a whole slew of new regulations and mandates because that is how we usually end up dealing with things, complete over the top knee jerk reaction. How many times has this happened to an airliner in this exact manner? Answer: ONCE. This isn't something that's occurring on a regular basis, this isn't a pervasive and debilitating problem that is happening over and over again and again like your monthly mass shooting spree (which we BTW have never done anything about) This most likely isn't EVER going to happen again.
But we're gonna make dog gone sure no matter what it costs us that IF it ever happens again we'll be able to find the wreckage in a timely manner.