The emergency services must work better with each other at major incidents to help them respond more quickly and "hopefully prevent future deaths", the coroner said.
Lady Justice Hallett said she could not accept that the police, fire and ambulance services could not do more to improve the situation.
All the services encountered "real difficulties" in locating each other in the immediate wake of the July 7 2005 terror attacks on London.
"As a result of there being no one common rendezvous point on 7/7 at which all emergency responders might liaise, the emergency services encountered real difficulties in locating each other's initial responders," she said.
"There was a significant failure, particularly at King's Cross, to ensure that there was a single rendezvous point where, in the very early stages, the first commanders could meet with each other, and with a responsible member of the London Underground staff, to find out what had happened.
"At the very least, as a senior member of the LAS (London Ambulance Service) accepted, there is more scope for sharing of information in the initial 'confused period'.
"I do not accept that more cannot be done to streamline and simplify the way in which the emergency services initially liaise with each other at major incident scenes, thus helping them to respond more quickly, with more accurate information, and so hopefully prevent future deaths."
Lady Justice Hallett added she was "concerned" there was no "uniform system" by which all the emergency services could confirm that the track current was off on the London Underground.
Such a system was "more likely to promote certainty, reduce delay and therefore minimise future risk to life", she said.
"I am concerned that more could be done, once confirmation has been obtained from the line controller, to disseminate that fact rapidly to all emergency personnel who are, or who will be, in the station.
"They all have an equally vested interest in knowing whether the power is off."
But she added she was "content to leave the precise means" of how this would be done "to the experts".
The coroner also voiced concerns that the network-wide "code amber" alert issued on the day of the attacks was not brought "directly and clearly" to the attention of transport agencies and the emergency services by London Underground.
"The fact that the Underground is being either suspended or evacuated, and that very large numbers of passengers (over 250,000 at any one time during the rush hour) are about to be disgorged suddenly onto the streets of London, are matters that London's emergency and transport agencies need to be informed about and there is a risk to life if they are not," she said.
"There is still no system in place for the alerting of others to the existence of a network 'Code Amber' or 'Code Red' or of an evacuation.
"London Underground accepted that it had not been 'sufficiently in the loop for the emergency services procedure'. I agree."