a sad shigure

With the -spd I think he wouldn't be very good.
He's in 4* pull so you can wait until you get another one and use this one for fodder or for merging (so you can make either a 4*+10 or if you want to invest more on him a 5*+10).

Harmonic Lance works best on anyone with a low CD special, I wouldn't imagine it would be a whole lot better on one unit as opposed to another.

Really, any Moonbow user would get the most out of it. Or, if you'd prefer, you could synergize it with Quickened Pulse Seal to allow for a higher CD Special, like Luna, Iceberg or Bonfire.

A Shigure with a speed bane is not "as good" as one with neutral speed, or a speed boon, but he's still an absolute monster when built decently. Even with a speed bane, he can run a Desperation set, or be a bulky flier, due to his absurdly high speed and decent defense.

Of course, if you still don't want to use him, then Harmonic Lance is a good choice for... well, honestly, probably any lancer, similar to how practically any and every sword unit can use Wo Dao (provided a decent build).