ragnarok1337 said:
It sounds like a contrived excuse so you can have your precious NanoFate.
First, two people who knew each other thousands of years ago just happening to meet on a street corner (and not just once, but several times in a short time span as Usagi and Mamoru do) is contrived no matter who it happens to unless there's some guiding influence behind the events taking place, and I don't mean that Fanon!Pluto is hiding behind a curtain somewhere.
Second, drop the tone. I can respect that other people prefer other pairings, but please respect that I prefer this one in return.
Third, as you pointed out already, without some kind of power-up Fate is going to be useless in the long run (and really, even within this arc; she has basically no hope of winning against either the Senshi or the Dark Kingdom without the plot intervening in some way) and I don't want that for her any more than I want the Nanoha characters to make the Senshi useless. Giving her one of the gold/silver crystals is my preferred way of keeping her plot-relevant as opposed to bullshitting something up like the aforementioned fusing of jewel seeds to her linker core. Other characters have other power-ups; Hayate has the Tome, which can be purified and possibly absorb Senshi magic in some manner to boost both her and the Wolkenritter if necessary. Suzuka and Arisa have the seeds of Uranus and Neptune, they've been all set from the beginning. Even Yuuno has the Infinity Library, which will be very important in the long run because of the Al Hazard thing.