In addition, for the spell progression, I would use this for every spellcasting class if it weren't too cumbersome to apply.
SpellProgression(class) =Min ( classlevel*2, (characterlevel/2 +classlevel/2)) )
This looks a lot like a system I came up with (and posted
here
All character classes have a magic rating, which increases by level much like base attack bonus. For a multiclass character, add up the character’s magic ratings from each of her classes to find the character’s total magic rating.
For example, a 6th-level wizard/4th-level rogue is treated as a 7th-level caster for determining the range, duration, and other effects of her spells. Her summon monster spells last for 7 rounds, her lightning bolts inflict 7d6 damage, she rolls 1d20+7 for dispel checks, caster level checks to overcome spell resistance, and so forth. She still doesn’t get 4th-level spells (as a normal 7th-level wizard would).
The following restrictions apply, however:
*Only the highest bonus is used.
*A character's effective caster level in any spellcasting class cannot be increased by more than three times the base value. For example, a Clr 15/Wiz 2 would normally gain 15 levels from his cleric side (so he would cast spells as a Wiz 17), but by this rule, he would be limited to Wiz 8 (he'd gain three times his base value, or +6).
*A magic rating gained from a class can't be added to that class - in this case, you use the next higher rating for the highest-level class. For example, a Clr 10/Wiz 8 would add 8 levels to the cleric, not 10.
A character's caster level in any spellcasting class cannot be increased to more than double the base value in this manner, however. For example, the Clr 15/Wiz 2 from above would gain two effective caster levels added to his cleric class (but he wouldn't gain any new spells); he would gain 6 effective caster levels to his wizard class, and 2 of those levels would be actual caster levels. So, in effect, he'd be a Clr 17/Wiz 4 with access to 7th level cleric spells and 2nd level wizard spells (as a Wiz 4).
If the character gains an equal bonus from all classes, the bonus levels from one class are divided equally among them all. For example, a Clr 10/Wiz 10 would gain +10 effective caster levels and +2 actual levels; these would be split evenly - Clr 20 (11)/Wiz 20 (11). That is, the character would have an effective cleric and wizard caster level of 20, and an actual caster level (for access to spells) of 11.
To borrow Wulf's examples as checks:
Clr 1/Wiz 19 = Clr 2 (3)/Wiz 20 (20)
Bbn 10/Clr 10 = Bbn 10/Clr 12 (11)
Wiz 10/Clr 10 = Wiz 20 (11)/Clr 20 (11)
So Trailblazer is certainly on course to be a Heartbreaker to the Pathfinder standard.
I thought Trailblazer was an adjunct/supplement for Pathfinder, hence the similarity in names.