Gara didn't actually take me that long. What honestly took the longest was that I didn't even try the lowest level bounty for about two weeks until I noticed it could drop one of her parts.
Nidus didn't take that long, about 18-20 runs. Now, Harrow is the one that seems to be taking me forever. I've done a dozen defection runs, and about half that many pago runs. No luck so far.
I'm looking forward to Khora, but I'm hoping she's not such a pain to get.
What I'd like to see are weapons that have one or two physical damage types and an elemental damage type as base.