VirtualWizard
Explorer
As written, I think that the 10' step is unbalancing because this ability allows a character a limited 'take 25' tumble check as part of a full round attack. The requirements to gain the ability seem rather low meaning that the ability to 'take 25' on a skill roll is extremely powerful for a low level character. With this ability, you will likely see a lot more sneak attacks and cleaves.
If I were to change this ability and the PrC, I would add Tumble 6 for entrance requirements. I would make the following changes to the abilities gained.
1st level add Tumble Mastery (Elemental ninja can take 10 on tumble checks)
1st level remove 10' step
3rd level add 10' step (remove ability to move through occupied squares)
7th level add Step Mastery (allow step through occupied squares w/o AoO)
7th level remove 15' step
10th level add 15' step
What do you think?
If I were to change this ability and the PrC, I would add Tumble 6 for entrance requirements. I would make the following changes to the abilities gained.
1st level add Tumble Mastery (Elemental ninja can take 10 on tumble checks)
1st level remove 10' step
3rd level add 10' step (remove ability to move through occupied squares)
7th level add Step Mastery (allow step through occupied squares w/o AoO)
7th level remove 15' step
10th level add 15' step
What do you think?