Not quite correct on Impulse as in DS9 it is put forward that starships cheat realtivity by throwing a Sub Space field around themselve, when at Impulse, to decrease the vessel's apparent mass. They Warp engines are used in a secondary capacity to do this.
Without a Sub Space field and reduced mass, Impulse maybe makes just 1/30th of light speed.
O'Brien suggests using the DS9's defelctor system to generate a crude Sub Space field to do just that in the "Emissary".
That's how the writer's managed to eliminate the E=MC squared arguments with how Impulse Power manages to push a starship to 0.99c in some instances.
It's in a 1970's Galelio shuttle technical blurb as well.
Impulse power doesn't power all ships to the same speed, as it depends on true, mass, apparent mass level achieved and maximum thruist of the Impulse Drive system installed. Not all starships can make 0.99c on Impulse Power even with a DSub Space field cheat.
No, Legacy is more like SFC 3 without any of the tactical options available.... you just keep shooting until one of you blows up.... it''s that simple.
Prepare for a nasty shock Klingon players.... the D7 has lost its 3 x bow Phasers in the interests of game balance.... shock horror!!

There are similar gun omissions on some Fed ships also.
You can't H&R, you can't T-Bomb, you can't launch shuttles, you can't launch fighters, you can't capture, you can't fire Drones, you can't overload Disrupters or any other weapons, etc.
Legacy has no tactical flexibilty for cunning players to utilise.
SFC should be more like SFC 2 EW with a Z axis and then some of the weapon's arcs would make more sense.