With small exceptions (e.g. most or all Masters only have one Servant), analogy between Sekirei and Servants is complete. The relationship with their masters is temporary in both cases, and they form deep bonds that must be broken (or maybe not! the temptation of the evil trade!). Both protagonists wish to put an end to the bloody game as well, and as I mentioned before, they both have to get a grip or else.

The treatment of the subject is different, of course. After all, Sekirei is supposed to be a fanservice machine first and Pokemon second. I have not seen anyone being killed in Sekirei, while F/SN is quite violent.

Since F/SN is more pretentious (or more story-oriented), Saber is a tragic figure with a rich background. I don't see anyone being built into her mold in Sekirei. Sure, Yume has some dark past, but she's not Minato's pokegirl, and so only peripheral to the story.