I wonder if the "help us Picard" was entirely deceptive. Was there some truth to it? Or was it just the Borg changing tactics and using deception instead of brute force as Seven said? Maybe the Borg do need Picard's help in some way and since the Stargazer refused to negotiate and raised its shields, the Borg just sent the Queen to expedite things since they are determined to achieve whatever their goal is? The fact that the Borg queen only stunned the crew instead of killing them, might suggest "peaceful" motives.
Also, since these Borg came through a temporal anomaly, I think these Borg might be from an alternate timeline. It would explain the different ship design, different tactics, not using the classic "resistance is futile" line, and the Borg queen wearing that cloak. Perhaps, these Borg behave differently than "our" Borg because they come from an alternate timeline?
My theory: we've seen hints from the trailer that in the changed timeline, the Federation has become some totalitarian regime. What if these are Borg from the totalitarian Federation timeline who escape to our timeline needing our help to defeat the totalitarian Federation? It might explain why they asked Picard for help. They might assume Picard would be sympathetic to helping Borg escaping destruction from a totalitarian Federation.