I always doubted that the 57 mm gun on the LCS was a serious gun.
The obvious counter to attacking speedboats would be flank speed away from them, using an armament to shoot at them before the ship is in the range of speedboat weapons.
A forward-mounted 57 mm gun was never a reasonable piece of kit for this. It doesn't have the range and lacks the field of fire.
FIAC's do by their very nature, have a very short effective range* (non-stabilized HMG's and rockets),
and the 57mm does outrange those craft, by a huge margin, even with current unguided rounds.
The guided ORKA-round will not extend the effective range, but it will allow the gun
to engage and the destroy targets with fewer rounds and potentially multiple targets per second.
As for using flank speed to maintain distance, that is not always an option.
ROE might not allow fire for effect at will, so the fight might begin with opponents on all sides, making a retreat impossible.
The mission might also be to escort other crafts, that the LCS cannot leave behind,
or might be in mined or otherwise restricted waters (archipelago for instance), that means that the LCS cannot run away.
More dedicated FAC's are a completely different beast, as they might strike from >100 miles away.
The real challenge the way I see it, is boats (and ground launched) missiles like the Brimstone,
with enough range and small enough launchers, to make it near impossible to destroy the missiles before launch
and with a large number of small missiles to destroy post-launch.