The only real use for Hull Restoration is to combine it with Best of the Best for +15% CR.
That assumes getting Leadership capstone. For me, that is not an option if I want to pilot my flagship and take Hull Restoration. Got to have Tech 2 for Gunnery Implants and Combat 5 for various skills. If I want to leave flagship on autopilot and let the game take full control of my fleet, then yes, maybe getting BotB would be an option. Piloting unskilled flagship is lame; I do not want to be the sidekick (in skill power) of my fleet.
If I want Hull Restoration, +10% max CR is all I expect to get from Hull Restoration; and getting that means giving up high Leadership (after taking Combat 5/Tech 2+/Industry 5).
That aside, I agree with the point once player can win flawlessly. At that point, player does not lose ships in battle, and probably is not interested in new ships.
What the Hull Restoration skill is missing is hull restoring effects. As in hull repair and CR recovery bonuses. It should do something like half the supplies consumed for repairing and CR recovery and quadruple the CR recovered each day.
I would love to play a fleet that can continuously fight battle after battle, repairing between fights and fixing up the odd ship that is destroyed. As a capstone it should have a noticeable effect on the core aspect of the game which is combat and rapid repairs can lead to a more reckless play style as you can quickly recover from mistakes.
It sort of does that already (when combined with Field Repairs), except it is still inferior to perfect play that does not need rapid recovery (because they did not lose ships in the first place). Also, crew still die, and you cannot chain battle when player needs to return to a world to get more crew after about three fights that involve partial fleet wipe.
Hull Restoration is a perfect capstone skill, that way. It forces you to play the way it wants you to, but gives you powerful bonuses for that.
It doesn't need any changes. If you don't want it to remove your D-mods, then pick the other capstone.
It is perfect... as a tier 1 non-combat/Crew Training alternative skill. As it is, it is too weak to be a capstone, especially since all of the tier 3 Industry skills are campaign only skills too, unlike those in Technology. With Hull Restoration, player gets a single tier 1 Leadership equivalent skill (after story point investment) for two skill points, one for Hull Restoration and one more for the tier 1 or 3 non-combat filler skill. (Hull Restoration needs four Industry skills as prerequisites, but only two of them are combat, although with how powerful Ordnance Expert is, maybe both tier 2 can count for three.)
The bonuses are powerful... for campaign side only. A skill that has campaign bonuses only and no combat power might as well be no skill at all. Such skills should be prerequisites for more powerful combat skills only. Gunnery Implants and Ordnance Expert are good examples of powerful combat skills that are stronger than typical tier 1 Combat skills and getting a non-combat skill to unlock such powerful combat skills seems justified. Unfortunately, Hull Restoration is no stronger than Crew Training, a tier 1 skill.
Whenever people show off their endgame fleets, Industry is always dumped, either no Industry at all, or just enough for tier 2. Meanwhile, BotB (which needs Leadership 5) is almost universal in those fleets, with few exceptions.