I've played about 5-6 hours of Starbound and I've only made it to a level 5 planet, but here are my thoughts regarding these changes. Armor: If you plan on removing armor entirely from enemies it will limit some of the weapon/combat mechanics. Without an armor value on enemies you reduce weapon choices down towards whichever weapon has more DPS. Example My KillKiller Poop Axe deals 50 damage and has an attack rate of 1 My Stabby Sword deals 30 damage and has an attack rate of 2 The Axe has a DPS of 50 where's the Sword has a DPS of 60. This makes the Stabby Sword the obvious choice. Now if you add in an Noisy Horse Beast that has say... a flat armor of 15, the choice becomes a bit more difficult. If you are constantly hitting the target with the Axe, you would be dealing 35 dps. With the Sword you only have 30 dps against that mob. As far as armor penetration is concerned, it could be a random modifier (percentage based rather than flat) that will give players benefits against armored opponents. You may only see differences in advantage between these weapons, but it's the little mechanics like these that make combat and gear choice more interesting. Scalability and Leveling: I think that getting rid of leveling numbers on monsters is a great plan. I would also say get rid of planet levels and replace them with a threat assessment instead. This leads me to my next topic Numbers: I think some of the mystery and want to experiment with weapons/armor is directly related to how much information is provided. If I see a weapon like this: Frozen Poop Sword: Damage: 25 - 35 Attack Speed: 2 DPS: 50-70 Armor Penetration: 10 On-Hit: 10% chance to inflict 35% slow to enemy movement and attack on hit vs a weapon like this: Frozen Poop Sword Damage 25-35 Attack Speed: Fast Specially forged by Avian smiths to cut through light armor. Blessed by the Ice Goddess of Sha' Krie to freeze the very core of those struck by this weapon. I can easily look at the top weapon and whatever weapon I'm currently using and make a decision on which to keep. The second weapon makes me go "hmmm, damage isn't bad and it hit's decently fast, I wonder what it does when I hit something with it" Then I will likely go test it out on a few enemies. While I technically get less information, the information provided is informative enough to tell me roughly how much DPS the weapon does, and that the effects it has could be really cool/valuable.
AP could work as a side mechanic like you describe. Something like only a small selection of enemies have Armor and maybe only when they are blocking. Like a creature with a turtle shell or a NPC with a shield can hunker down and gain an armor bonus. That would let high AP/high single hit weapons work as a turtle cracker well having lower overall DPS
I forgot to mention that, armor should only be on a subset of enemies. I didn't think of the shield idea though, I like that idea.
