Buff or custom AI squad mates?

Sorry to be a bother, was just wondering if there was a way to seriously buff AI Squad Mates, or give players the option to bring in their custom classes as Squad Mates? 

I haven't played since the end of September when all the patches were first going on, but managed to get Bulwark and Tactical all the way up to Level 25 with a good amount of purple weapons and armory data. I don't know if it's just my luck, but after working on my Vanguard for awhile I tried Ruthless but EVERY TIME, the Team Mates got just abandoned me whenever a Wave happened, trying to get to the next area, leading to me dying and then them getting overrun too and we losing the mission.

Every. Damn. Time.

So I tried it Solo, only to get jumped by what felt like at least 14 melee Majoris enemies while another dozen with sniper rifles were shooting me from afar and giving me literally no room to think, let alone breathe while my AI Team focused on the Minoris enemies for some reason.

Three times I did this, and three times it happened before I even left the first area.

It wouldn't be so bad if the Relic weapons weren't locked behind having to do Ruthless, and I've suggested before maybe doing a trade system (10 greens for a purple, 10 purples for a Relic), but between useless/underpowered AI Squad Mates or human Squad Mates that just straight up abandon you and then get torn to shreds, it doesn't seem like casual players will be able to reach Relics.