1: Something needs to be done about the healer, but whatever you do it will be a temporary measure. Healers don't typically pick up medals since they're already high priority targets, so after the first couple kills you won't be earning many points for defeating them. Rather, the goal is to ensure someone keeps them occupied while the rest of the party bursts down more lucrative targets (DPS with a fair amount of medals, or tanks with a LOT of medals). This can mean DPS killing them, or a tank stunlocking them, or even your own healer CCing them.

2: People would rather you didn't queue up for 4v4 solo while inexperienced. Yes I know 8v8 is an entirely different beast but... still. 4v4 is the best way to get experience for 4v4, but people WILL hate you.

3: Tank typically takes medals first, as their defensive skills allow them to keep the enemy team from taking them back. The heavy medal status keeps them from taking ALL the medals though, they'll just become a squishy loot pinata if they do. So DPS ought to grab some medals here and there. Healers tend to get killed a lot as it is, so they should only grab medals as a last resort.