I'll keep farming for the better speed gear! I'm sure after another month I'll be able to get those speed stats up. In this case, it looks like I would be removing Apothecary from this team. Who would be the best AOE DEF down to put in? I have Warmaiden at lvl 60, Zargala and Aleksandr both at lvl 50, and Dhukk at lvl 40. I could go with Warmaiden once I get seeker leveled and geared, I have her at SPD 182/ACC 266/CRate 34% so obviously lots to improve on.
Zargala is a straight upgrade over Warmaiden. No question she is better. But, can you afford to book her? She absolutely needs her A3 booked four times, to bring her chance of landing the debuff to 75% (80% with Sniper). The same goes for Alek - he needs his A2 booked four times to have a 100% chance to land debuff. Dhukk needs five books on his A2, and needs to land a critical hit as well.
If you can get the books, then yeah, absolutely swap WM out for any of those three. If you can't, then stick with WM. The fights you'll lose that you would have won with one of the others are few and far between.
Regardless of which one you pick, you need to make sure they have enough accuracy to land the debuff. That's the most important part. The relevant equation is that you want ACC between -20 and +10 of their RES. At your rank, it's unlikely you'll be facing high-resist teams, so you can probably get away with as little as 150 ACC, though I'd probably want to have at least 200 to be safe.
Lastly - don't forget Perception / Swift Parry. You can reach 270 speed without any speed set items at all, if you go with those sets instead.