Improve and evolutive ships for hero

It would be nice to give the possibility to improve the heroes' ships (with new models specific to the hero class)

 with certain levels :

•  Level 20 medium ship (cruiser or destroyer)
•  Level 40 huge ship (dreadnought)

The modification is optional and increases the maintenance cost of the hero and uses fleet locations like other vessels.
It would also be interesting to add modules specific to heroes :

• Increase of experience gain per turn (1xp / turn per module)
• Reduction in the cost of maintaining the fleet (-5% per module)
• ...

This would also unlock new combat cards :

• Adrenaline: armament and defense more effective 25% on one phase (short / medium / long range) and less effective 50% on the other two.
• Increased performance of one class of vessel (small / medium / large) by 10% for both factions and reduction of other classes by 33% for the user only.
• ...