problem of combat prep is that it's not always applicable (or you already need to know the game). Some combats are scripted (like naval combats). In this game, stealth, pickpocket, traps... feel like abusing the system. It's really one thing I hate with deadfire rogue. Backstab, invisibility etc... mostly used to kill one enemy, reset combat, kill another etc... Instead of tactics you can use during a normal party fight.
Since they introduced bombes, they could have included traps as a new combat consumables using the same skill. More variety for the bombes.
Stealth : Like I proposed in first post, You should be able to restealth in combat. A 1 per encounter use like for athletic. That would make stealth usefull in all combat situation.
Pickpoket : why a separate skill? You must use stealth to steal... just merge it with stealth, like explosive & mechanic.
Backstab: I really dislike the weapon dmg bonus... because the rogue already have sneak attack & deathblow. Why not make it a passive that boost any martial ability used from stealth? I'm unsure power level affect martial abilities (I think someone reported it boost base weapon dmg?), but I would love if using a toxic strike from stealth with backstab actualy make the poison more potent. Same for crippling strike bleeding, or boost the bonus of a finishing blow etc... Boost the PL of the next attack ability. That would allow it to work with dual weilding too. Assuming PL change something with weapon abilities.
In my opinion, the skill system is a mistake. When you don't know the system, it's really obscure what the value represent. I really miss the generic abilities from POE1, and the ones introduced in deadfire are uninspired.
They could have introduced a general ability tree linked to character level and not PL (so doesn't mater if your solo or MC). Like in poe1 it work like the feat system of POE1. Instead of abstract values of the skill, introduce passives like a boost in alchemy duration (+x% duration), more potent alchemy etc... Bluff, diplomatie etc... could be passive that when you unlock just give you the options in dialogue.
And more important, reintroduce the active abilities, like viper strike, stealth could be a new invisibility ability (with a cooldown when out of combat?), same with pickpoket. Add some new 'general' martial and spell abilities (like arcane assault)... That would allow a wizard that use conjure weapon have easier acces to some martial abilities.
The power level system is a great idea, just completly underused. Why not every abilities have keywords? Exemple, why Toxic strike don't have the poison keyword? With more gear and passives that boost power level of different keyword, more build options. Cipher spells have keywords but you don't have any gear that boost them.
Instead of skills points, you boost your social abilities through power level. The advantage, is that you can make social abilities and combat abilities share some keywords, so you boost both. Exemple : charm & persuasion : make them share a keyword, a cipher or chanter with strong combat charming should be able to persuade more easly in dialogues.
Steath, smoke veil( invisibility), escape, pickpocket etc... give them illusion keyword, and perhaps some new rogue only keyword. Someone that master illusion should be more potent with these abilities.
Keywords should work as some sort of sub specialisations that can apply to any class.