+1 is weaksauce
Seeing as I did away with a flat AB or level based bonus and replaced them with weapon skills, it seemed logical to apply the Skill Focus feat to combat skills as well as non-combat (though skill focus gives a +3 bonus in both my games).
In the Star Wars conversion, losing levels meant no +1/2 level bonus to damage. However, hit points went down as I instituted a maximum hit point rule of 5x Constitution (Hit points are gained by repeatedly taking the Toughness Feat). So far I'm leaving damage alone, as the bad guys have less as well as the players.
In 4e, it's a little different. From what I read on the web, a lot of GMs, including WotC's developers, have issues with how long fights last and take measures such as nerfing monster hit points. I had been having players add their 1/2 level bonus to damage, but no more levels means no more bonuses.
Weapon Focus gives +1 damage with a weapon group, going to +2 at Paragon and a whopping +3 at Epic. A Level 1 Kobold Skirmisher has 27hp, while a Level 4 Slyblade has 42hp. How impactful will that +1 damage be, let alone how feeble that +2 at Paragon looks against a Level 11 Firelasher with 108hp or +3 versus the 255hp that a Death Giant has?
Actually, I think writing this has led me to an idea. Have the feat Weapon Focus add 1/2 the skill rank as a damage bonus to that weapon. So a fighter with 8 ranks in Heavy Blades and the Weapon Focus feat would add +4 damage. As he buys up his Heavy Blade skill, the damage will scale.