So isn't it almost always prudent to pick up a single level of wizard in this type of build?
Your average caster level with a build like Mystic Ranger 10/Wizard 1 should look something like:
7 (Shooting Star Improved Spellcasting: half level + 2) + 11 arcane class (Shooting Star Improved Spellcasting: Sword of the Arcane Order: Wizard class levels + Ranger class levels) = 18
Even at sixth level with a Mystic Ranger 5/Wizard 1 build you'll be getting a CL of 10.
ok, what do the feat and substitution level say...
Benefit: [...] If you also have levels in wizard, your wizard caster level is treated as the sum of your wizard, paladin, and ranger class levels.
Improved Spellcasting (Ex): When casting ranger spells, a Shooting Star can treat her caster level as equal to one-half her ranger level +2. If she also has arcane spellcasting ability from another class, she can add her caster level from that class to this value to determine her caster level.
now let's take a look at this...
the feat explicitly says that your wizard caster level is exactly "the sum of your wizard, paladin, and ranger class levels". in the case of a ranger10/wizard1 this is 11. (note, that without a level in wizard, when casting wizard spells your caster level is one-half your ranger level.)
the substitution level says that, "when casting ranger spells", your caster level is "equal to one-half her ranger level +2" plus the caster level of any arcane class you might have, in this case 11, thus your ranger caster level is indeed 10/2+2+11=18.
lol, thanks for showing me this! i doubt that the majority of DMs would allow that, though.
btw, if you take into account that a mystic ranger has the spellcasting ability from level one, and rule that your caster level is equal to the mystic ranger class level (with caster level=ranger/2 the mystic ranger could not cast spells at 1st level) the ranger caster level increases by another 3 to 21.
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on the access to the wizard spell list thing... i'd like to give an example:
you have the license to keep sheep and a stable which is licensed to keep sheep in. then, you acquire a license for said stable which expands its license from only sheep to sheep and goats. now you have a license to keep sheep and a stable which is licensed to keep sheep and goats in.
this, however, does not automatically mean that you are allowed to keep goats, too. it only means that you could also keep goats in the stable if you had the license to keep goats.
(if this is too rural for you, then you can change the stable to a research lab, the sheep to white rats and the goats to chimps.)