I'd be fine with most of that proposal, but I am a bit concerned about treating troop ships the same as decoys or scouts. In the large-grain treatment I would lean towards thinking that troop ships should probably count like armed ships, at least with respect to attacks by planetary defenses. If an attacker could count on troop ships not getting attacked until a round after which all armed ships had been destroyed, it would be easier to plan an attack that includes enough troopships to capture a planet, with just enough armed ships to take down shields and act as fodder to shield the troopships, which could then capture the planet. I'll acknowledge that the issue does kind of go both ways, troop ships could act as fodder to protect armed ships, and just like now, it is still possible to plan that kind of attack even if the troop ships are valid targets. But I have a different proposal to at least partially help with that--Geoff the Medio wrote: ↑Sat Sep 01, 2018 10:33 am...make combat target selection ignore unarmed ships (ie. those without direct weapons or fighter parts) unless there are no targetable armed ships present. Combat could still be used to take out troop ships (but only after all armed ships defending them are gone).
Right now, when planets attack, they get just a single generally-very-strong attack. I'd propose that planet defense attacks be considered like an amount of energy per round, that can get divided between multiple targets-- if a planet with 40 defense targets a ship with just 10 structure, it would still have 30 more points of energy damage to inflict that round on other targets.
Another possible tweak could be that planets would prefer to only target armed ships so long as the planet has shields, but as soon as they lose shields they also start targetting troop ships even if armed ships are present (and that would be especially effective if the planet defenses could attack multiple targets like I propose).