Hey, back back with a couple ideas! These came into my head after playing LOTSB, why not have missions where you have old characters join your squad? I don't know about you, but I'm kinda tired of the attention jammed onto Liara, Garrus and Tali (Blasted Dextro-Amino/Pureblood Biased Bioware!). Here's what I got so far

Gateway to the Underworld

Squadmate: Aria T'Loak

In this series of missions, Aria T'Loak will accompany you as a squadmate as you reclaim Omega. Cerberus has been using Omega as command center for their operations in the Terminus Systems, reclaiming it will not just cripple the Illusive Man, but give you a tactical advantage in the Terminus Systems.

Turncoat Mercenaries

Squadmate: Zaeed Massani

Zaeed has come forth with some shocking news; Darner Vosque, the current Blue Suns leader, is indoctrinated. You must help Zaeed take down Vosque so he can assume control of the Suns and lead them in the right direction. If you did not recruit Zaeed in Mass Effect 2, he will be a lot less friendly to you (not that he was mr. rainbows and puppies to begin with). If he was not loyal to you nor survived Mass Effect 2, his role will be filled by Lieutenant Gharik, a Batarian Special Interventions Unit operative, who will offer some surprising insight on life in the Hegemony.

Breaking Ranks

Squadmate: Urdnot Wrex/Urdnot Wreav/Urdnot Grunt or Major Kirrahe/Lieutenant Tolan

Wrex Powers:

Wreav Powers:

Grunt Powers:

Kirrahe/Tolan Powers:

Prerequisite: Priority: Rannoch

Now this mission will pan out in different ways dependent on what choices you've made:

If Wrex survived Virmire and you didn't sabotage the Genophage Cure, he will accompany you.

If Wrex didn't survive Virmire, Urdnot Wreav will accompany you regardless of whether or not you sabotaged the Cure

If Wrex survived and you sabotaged the Cure, Grunt will accompany you.

If Grunt wasn't loyal, died at the Collector Base, nor accepted into Clan Urdnot, his role will be filled by either Major Kirrahe or Lieutenant Tolan.