My two cents worth:
1. Better AI. (The bane of most/all computer games. Interestingly, chess at all but the highest levels, is now dominated by computers. So maybe there is hope for wargame AI)
2. From latest research, these vessels did not sink, even with gaping holes thru the hull. They were known to float around as flotsam for months and finally break apart before sinking.
3. Ram speed was probably not fastest speed, as you didn't want to bury your ship deep in the enemy vessel. Even a smaller vessel, with all its mass energy focused on the relatively small ram, would bash thru the hull fairly easily. The trick is to use ramming speed to avoid being hit, or to set up the enemy vessel to be rammed. Then it's oars out of the water and pulled back, and prepare for collision. So, more difficult to ram, but when successful, almost always sinks the rammed ship.
4. Some control of missile fire: focus on one target, etc.
5. The above assumes, of course, that there is still some interest in this game.
All the best