I've advocated in the past they should allow clerics to have 2 mercs so we could field both a tank and a dps. But they have simple tools already at their disposal as evidenced by the current expansion's huge upgrade to our Mark spell. For example, they could add a Merc-only version of Retort that has an even stronger damage component than Mark with a higher proc rate. A 1-2 million damage proc hitting several times a second would be awesome fun. And it could help alleviate the tank merc's problem holding aggro on multiple mobs at once.
This is not a complicated problem. It doesn't need 2 mercs or any other complicated implementation.
Copy and paste MAG/NEC swarm pet stats onto the cleric hammer.
Heal the hammer. Nuke/Stun the mob. Use a wizard merc. S/Molo CLR LFM/LFG.
The only complication is changing the minds of the people not willing to admit there is a need for change in the PUG startup/forming process.
This is not 1999. All classes need to have an enriching solo/molo experience with class synergy/aDPS being the motivator for forming a group. 1+1=3.
Everyone should be wandering around the world doing something, bumping into new people and forming groups, instead of sitting in the PoK/GL/GH twiddling their thumbs because they can't do anything alone.
Actually, it should be 1999, because that's exactly how PUGs got started in the OG.