Actually, I don't think it's a particularily good escort. It suffers from the same problems Hellebore used to have in eldar list - it has weapon loadout with little internal synergy. It might seem universal, having weapon for every occasion, but in practice it never can use its full potential.
Ideally, it should be both on lock-on and reload ordnance every turn - otherwise either lance is not working on full effectivenes or it can't fire its torpedoes. So in no way I see it as overpowered. It's just paying a bit extra for flexibility. [I agree it should have bigger price difference with idolator, though. Lance itself is worth it.]
I'd think about changing its lance fire arc to F. With l/f/r version it would almost always be in position to lock on, making torpedo choice inferior in most cases, and turning them into effectively one shot weapon. Reducing the range isn't necessary, I think, but I agree that 45cm lances on escorts need to be treated carefully when desigining rules.
Also, I'm fan of changing those heavily armed escorts to 2 hits. They should have more mass and size, just to house all the weapon systems.
