Create a 'PvE only' skill per profession (like the Sunspear skills) that does not use a title track as the associated attribute but instead is made more effective by the number of different professions in the party.
The main purpose of this idea is to let players continue to PvE their chosen class instead of dressing up as a bear to get a job done.
This would obviously benefit the group players in the 8-man areas and be of little use to solo players but the idea is to be more inclusive than exclusive.
Maybe even make 2 skills per profession, 1 offensive and 1 defensive and make them elite so only one can be equipped.
The skill(s) should not be spammable and maybe put a high cost on it to ensure that it is not over-used but with careful utilisation, including some team coordination, will swing a battle in the team's favour.
This way I think a sensible balance can be achieved. For example, if you decided to add a second ele and another monk instead of adding that mesmer and that rit then the whole party will not get best use out of this skill.
I don't PvP so will not speculate if such an idea would work there.
/adopts the foetal position
P

I have no idea what you are saying.