Voadam
Legend
Skills, pick one list and go with it. You don't need to adjust class skills needed, the 3.5 class skill adjustments were adjustments for the classes (like making rangers more skills oriented by bumping up their skills per level) not an adjustment to the specific skill list. My house rules was everybody got at least 4 skill points per level so people had a higher minimum skill competency.
- Skills
- Monster spacing instead of facing
- Damage Reduction
- Ranger, Monk.
I disliked the fiddliness of facing in 3.0 at the table in combat so I liked the abstract 3.5 square monsters and adjusting shield to be a straight defense and not a directional one. It would be fairly easy to change 3.0 to this rule straight with very few complications.
I went with options to use either variety in my game, so sometimes you needed a +2 sword, sometimes you needed a magic cold iron one. If you go with 3.5 alone just use the values from the 3.5 MM for monsters and things like the 3.5 sources for things like the stoneskin spell. It is mostly a matter of flavor taste whether you want to require higher plus weapons to hit mid level devils or silver or good ones.
Ranger went from front loaded specialized lightly magical fighter to more fragile higher skill warrior with some magic. You can pick the one you like better or go with both as options really. The 3.5 one has fewer dead levels. My house rules was to make their favored enemy a flat bonus instead of type specific for combat and have the favored types count for skills so they have a more defined universal combat niche.
For monks the big switch is not having the different BAB iterative chart for flurry. I felt they were underpowered melee combatants and house ruled them to have a phantom +1 to hit on levels when they did not get a BAB to avoid the flurry of misses.