There's no "official" news about the Wing Commander: Standoff mod... but Quarto was recently good enough to update the forums with some interesting details about Episode 4:
On the winning path, you have 3 Sabre missions, and 2 Rapier missions. Apart from those, you also have 2 missions where you choose between Crossbow, Sabre and Rapier, and 1 mission where you choose between Sabre and Rapier. Of course, that includes all the alternate missions (in particular, the two Crossbow/Sabre/Rapier missions are alterates of each other, so you'll only get to play one of them) - alltogether, without playing alternate missions, you'll fly 6 times on the winning path, with 4-5 opportunities to fly a Sabre, 3-4 opportunities to fly a Rapier, and 1 opportunity to fly a Crossbow.
If you're one of our new readers following the Wing Commander Arena announcement, then you should be sure and give Standoff a try -- it's a loving tribute to the original series built on the Wing Commander Secret Ops engine!
On the losing path, things get a bit more confusing because there's more alternate missions. There are 5 Rapier missions and 4 Sabre missions. There's also 1 mission where you choose between Crossbow, Sabre and Rapier, and 1 where you choose just between Sabre and Rapier. All told, sticking to one path, you'll fly 5 or 6 times, with around 4-5 opportunties to fly a Rapier, 3-4 opportunties to fly the Sabre, and 1 opportunity to fly the Crossbow.
So, I think pretty much everyone should be happy with the choices provided. Unless of course you happen to like the Crossbow... or the Stiletto . All I can say is that they don't get many Crossbows on the Firekka, so they're used sparingly... and you haven't quite seen the last of the Stiletto, either. Definitely no more Gladius missions, though - on very rare occasions, you might see your wingmen flying a Gladius if there isn't enough Sabres to go around... but if that happens, you can expect to be grounded soon, since Commodore Reismann doesn't much like wing commanders who lose all their ships.