Wow — mixed bag of emotions trying to answer that question.
Of course… the “Hey, what plugin did you use for that effect?” is usually answered with “go home! I spent 21 hours doing that piece by piece.”
YET — there are plugins out there like Trapcode’s (and others) that give you added functionality in AE that you won’t find on your own in there.
AND — other plugins like the Magic Bullet suite (and others) GENERALLY are things that you could create on your own using the plugs you are given by Adobe.
SO — don’t worry about not learning AE because you’ve bought all these plugins… worry that you didn’t use AE because you never USE AE.
Yes?
CaptM