Concerning Niche Abilities:
It's important to note that during 3-book APs you will only get to use your 1st level ability, and in 6-book APs you will only be able to use your 10th level ability for about 3 levels. It will be rare that you will ever use your 20th level ability and if you get the chance, it's not for long.
I suggest that another (a 4th) Niche Ability should be added and spread-out more evenly so the PC will get some real usage out of them (note: I realize that they scale by level, but the Evo won't have much diversity and may develop into more of a 1-trick pony w/o more abilities).
My suggested spread for the 4 Niche Abilities:
At 1st Level - can use the ability at creation... and
at 6th Level - can utilize this ability within a 3-book AP... and
at 12th Level - can utilize the ability within a 6-book AP... and
at 18th Level - (high-level AP) will have some time to enjoy using their top tier Niche Ability that may also scale for 2 more levels, where it peaks.
The Evo could really use another level (gradient) of evolution.
