For all PvP there's a meta game. Players find trends that are strong, and that becomes the meta that is generally expected from the community. This continues until someone finds a system that beats the current meta, and it evolves and changes.

There is no right way to do frontlines, there are simply strategies. All strategies have strengths and weaknesses.

For example full heal parties have little to no chance of winning the objectives in the Helidrome. They are however very strong at holding flags because it's nearly impossible to kill them.

Hint: Make sure you win the helidrome and focus another flag. You don't have to "beat" 1 specific party to win frontlines.