The idea behind the suggestion is that it will allow players do what they came here to do.....to play, while the system finds the group for them, so they will then play with others.
At the current state, you have all people spamming for people in global to the point where you won't be able to read the messages quick enough. In addition, it hinders your ability to play. So, if you want to do a dungeon, you can't go quest and kill stuff while looking for people. You have to use chat, wait for replies, and, as you mentioned earlier, tanks/heals are not that easy to find. This whole process removes all the fun and becomes a constant capitalistic race as to which company(group) hires the best candidate (player) for the job (heal/tank/dps) faster, so that it can profit from it.
Bottom line, this isn't about being a problem or a solution. The solution is already out there, it's just not accessible for some illogical reason*.
*illogical reason - disable RDF to socialize between players.
Socializing over global is near-immposible due to constant streams of spams and trolling (This is not exaggeration. I believe most of the people would agree on this.)