I just based that on who has the lowest survival rating in Hold The Line - so far as I can remember at least, but I definitely took Jack and Tali with me to go kill the Derp Terminator on the basis that that kept them 'safe' from the equations working out if I'd maxed out the team enough for everyone to live. Probably would've been fine anyway, I did everything before triggering the ending mission set.
Given the absence of any 'modern' tech for Tali to work her magic on, she'd probably be legitimately 'weak' (compared to the others, anyway) against the Punishers (although she's still got Chik'tikka, so that's something). If we assume biotics are a game-breaker, and also don't want to introduce other wrinkles like Kasumi cloaking herself and so on, that leaves Zaeed or... actually just Zaeed I guess, I was going to say Jacob, but I looked him up and turns out he was a biotic too. Never took him on missions, I forgot that (Kasumi/Samara every time). Actually there was his loyalty mission, I must've had him along for that; guess I just wasn't paying attention to whatever he did in fights anyway (I mainly just concentrated on lining up headshots and let my companions get on with whatever they felt like they should do).
