Rise of the Runelords

Spells
The following is mainly dedicated to the new lines of spells that replace the polymorph spell. Access to non-core spells is being limited. And one spell is being removed from the game altogether.

Removed Spell
Find the Path (Brd 6, Clr 6, Drd 6, Knowledge 6, Travel 6)

Non-Core Spells
Use of non-core spells is being limited for two reasons. First, even though most of these spells have been gathered from their myriad original sources and are available at several websites it still requires some time to sort through them to find the spells you might be interested in having. This action itself is a form of min/maxing and benefits the player who takes the time over the one who doesn't. Second, some of these spells are unbalanced, which can create playability issues. We are all guilty to some extent of min/maxing our characters, but I would rather not include such a large incentive to do it.

Access to non-core spells can be gained in two ways. The first is during play. (e.g. The party finds a non-core spell in a captured spellbook.) The second is through roleplay and the use of favor and influence points the characters may have gained. See the section of Favors and Influence.

No matter how the spells are gained, characters may never have more levels of non-core spells at their disposal than their character level + bonus from the applicable ability (Int, Wis, or Cha).

Polymorph Problem
From the Pathfinder Rules:

Of all the spells in the 3.5 rules set, none has caused more arguments or been more abused than polymorph. Such problems stem from two sources. First, the spell has never been very clearly worded. What abilities you gain and lose are always subject to question. For example, do you lose your human bonus feat when you take on another form? Second, the spell relies upon the balance of monster abilities to function. When you consider the fact that there are thousands of monsters to choose from, and some are more powerful than others of an equal Hit Dice, this problem becomes apparent.
To alleviate this problem, we have broken the spell down into a host of other spells that allow you to take on the form of creatures of a specific type. The spells themselves grant you bonuses to your ability scores and special abilities. This means that we can balance the spells against each other, rather than against all of the monsters ever printed. So while your abilities won’t exactly match those of the form you take, you will look like the creature and be able to do a number of the things the creature can do.

Metamagic Components
To add yet a little more variety to spell casting beyond the normal metamagic feats, the use of metamagic components will be implemented. You can find all you need to know here. In short, by using an additional component, a caster can apply a metamagic feat to a spell without increasing its spell level.

There are two change(s) from description found in Unearthed Arcana. First, the metamagic components are in addition to any normally required material component. Second, the caster must have the relavent metamagic feat in order to be able to use any metamagic component.