Right now, everyone declares actions, each side rolls a d12, and each combatant adds DEX bonus and if casting subtracts the level of the spell. This makes spell-casting a bit dicier and keeps things less predictable at the expense of rolling each round.
What the linked post proposes is that instead of rolling Initiative, use combat bonuses to determine order.
Since Skill20 doesn't use CB, I would have to use skills. In a way, it makes sense, as you would expect a highly skilled fighter to have the edge, and a more experienced spell-caster may well be likely to get his spell off quicker than a novice. The down side is that a halfway decent caster would be safe from lowbie monsters interrupting his spells before they went off.
I would need to keep the random element. Possibly have each side roll a d20 and individuals add their Skill/DEX asset to determine individuals scores (again, reduced by spell level for casters). That way Mr. Wizard wanting to fireball those pesky goblins would still be at risk if the dice were evil. The downside is that it might be too much swing.
A possibility is to make the opposition's Initiative static, effectively a DC to check against to see if you go first. So goblins with 2 ranks of Melee and a +2 DEX bonus would have an Initiative DC of 14 (10 + 2 + 2). If Mr. Wizard has 10 ranks of Magic, a DEX bonus of 1, and is casting Fireball (3rd level spell), he would add 8 to the Initiative die roll, meaning he would get his spell off on a 6 or better.
I opened my combat rules document to type out new Initiative rules. My current rules for Initiative is one paragraph, two sentences. I decided to leave well enough alone.