There were many key multiplayer components that never made it into Destiny, including voice chat, and a decent matchmaking system, and whilst these features were not added at launch, Bungie have suggested that such features may eventually be added if the community requested them.
One of the mentioned features included a proper matchmaking system for the raids in Destiny. So far, it can be difficult to find a decent group of players willing to complete a raid, and some players have voiced their frustration about this.
One of the most popular raids at the time of writing is the Vault of Glass, but without a group of friends to play with, it's proven difficult for some players to complete, considering that there is no matchmaking available for this raid.
Bungie talked about this issue, and described that whilst they would like raids to be more accessible, some of the stories of players interacting with one another are a reason why matchmaking wasn't added into the game at launch. David Dague from Bungie made a post to address the issue.
"The Raid was designed for solid teams of killers who have made a commitment to solve a dense and explosive riddle. Most of the raiding parties who have emerged victorious from the Vault of Glass have sworn that one weak link would have doomed their chain.
"There have been other stories, of course. We've heard tell of Guardians who met each other just outside the door that leads into that vault. Strange tales have reached our ears - tales of total strangers who have banded together to see the Raid all the way through to a triumphant finale.
"Those stories surprise us, but the players of our games always have. The best I can do to answer your question is to let you know that you've been heard. We're having conversations about how Matchmaking might support the more challenging activities in Destiny. It's a start. Keep sounding off about it, and maybe someday some matchmade Fireteam mates will hear you, too."
Personally, I see no harm in adding matchmaking to difficult raids, this approach would at least give solo players a slight chance at completing the mission.