That makes no sense at all. So he will ask for help because he knows that even though the Federation is at stake, she will be more likely to let the mission fail than to risk herself for him? So THEREFORE, he should ask HER? Whoa! That makes even less sense than the episode does.
Seriously you're picking some unreasonable nits here. Multiple posters, myself included have given a variety of reasons as to why TNG characters aren't being recruited to assist Picard. I have a sneaking suspicion though that if this show was just a roll call of TNG guest stars you would take issue with that as well...