Actually let's be clear about this one thing for further discussions( i've seen this point has been mentioned previously in the thread).
The ability to close the gap, is not utility for a specific context( solo, or group etc).
It's a general need of a melee spec/class in order to stay competetive in the game.
I.e a melee gap closer will be as useful in a warband, group, solo or regardless of context, is a must have tool for every close combat spec to even stay competetive vs the whole spectrum of ranged classes, kiters etc.