I dont think making a rouge's ability to hit better is going to make another class useless. You arent taking into account the bonuses fighters get and that by what I suggested the rouge doesnt get the +4 bonus, then they become close to even. But the difference is a rogue is taking rounds to be hidden and another preparing just to be on par with a fighter, while the fighter is getting 2 or 3 hits a round.
Also adding your level to stunning fist doesnt sound that ridiculous. A few times a day you can use your most powerful attack that as a monk you took years to master, the bonus wouldnt be broken at all.
Phobos had the same arguement and actually had me convinced for a moment. However I'm inclined to say no. Both the Backstab and Assassination are devastating attacks that do massive damage or kills which is why they are as inaccurate as they are. Imagine the Fighter's ability to hit with the Assassins ability to instantly kill you, from a player's perspective it seems awesome but from a game designer or game master point of view its excessively powerful. One might argue that aking a round to prepare should entitle the theirf-type to a better chance of hitting but I argue that it gives them +4 to hit and either a multiplier on damage or a chance to finish a target instantly. It sucks that it is so hard for a character with low BTH to connect with an attack but its
supposed to be hard that's why their BTH is low.
Stunning Fist allows a Monk to hit his opponent in such a way that they are bewildered or rendered stunned. The years of training teaches him how to do that not how to hit better. His BTH goes up every level that's how he gets better over time.
After talking to Phobos I went back to the book to contemplate allowing the addition in my current game but I oticed something very crucial. The addition of level is only to
skill checks involving class skills. All class skills that incorperate checks are listed with the associated attribute clearly displayed:
example. Hide (Dexterity), Poison (Intelligence), Disguise (Charisma), Turn Undead (Wisdom)
Primal Fury, Combat Dominance, Backstab, Stunning Fist, Divine Aura, etc. do not list attributes because they are not skill check thus not privy to the addition of level.
Now with that said this is C&C made for simplicity and roleplaying. Am I giving level additions because its a skill? No. Would i give it to someone that roleplayed a sick backstab? That is a completely different story. I have added to people's attacks on sereval occation but it was situational not automatic. Ask Sinn and the Stone Giant Daichi Assassinated that would have smashed him to paste.