I didn't say it was incompatible I said it was different. Different just means that you have to do some learning to get it to work in Pathfinder. By the way this is very, very similar to what was a popular line of thinking post Arcana Unearthed. I myself had a very similar concept to this back in the day. So I know it is good.
Here is my rule for multi-classing that I think pathfinder should adopt:
You add 1/2 your other levels to your class to advance *all* of your class features but no more than double.
Example:
Rogue 2/Wizard 6
Counts as a 7th level wizard
Counts as a 4th level rogue
They get all bonuses and class features as though they were of the particular class and level.
Note this is highly simple and portable. Nothing extra is really needed to be known to make this work. What do you think?
