Rainbow Dash is inpsirational to athletic girls, or girls who are curious about athletics, as her strength, speed and stamina are amazing, and she shows that hard work and determination can accomplish anything, whether it's a Sonic Rainboom or being the captain of like every sports team.
She's also inspirational to children with difficulty learning in school. She obviously had a major problem in Testing, Testing, 1, 2, 3, and it showed that just because she had trouble learning a subject, even with different means, did not make her stupid. She just needed a different method of instruction.
She is also inspirational for teachers, as this same episode shows a prime example of why differentiated instruction works, particularly for students who display difficultly learning under certain learning modalities. Rainbow Dash was able to learn the history of the Wonderbolts via a combination of the visual and kinesthetic (via her flying) modalities.
-PiratePony, M.Ed., Curriculum & Instruction