its about giving us a bar showing all our allies name / hp
i will tell why..
imagine a big fight, you are sedna, and you ally is hidden without 15 mob, and not targettable, and about to die
it did often happen, especially in late games with giant and everything
so with a party bar, you could target him from there with the spell
this thing is mostly an essentiel thing that i ask, rather than a mere suggestion 
its important, and vital , especially for support classes that can put buff on allies
thanks