The only part I would disagree with is the assertion that learning a second language "isn't really different" than learning a native language. My wife, who has a masters degree in theoretical linguistics and teaches English as a foreign language, has spoken to me several times about the differences between first and second language acquisition.

(Many ESL teachers are simply English speakers living in another country, but many of them are also like my wife, doing what is essentially applied linguistics.)

Other than that, I completely agree. The notion that you are simply doomed to only have one language after the crucial period is exaggerated, and the key to learning another language is immersion.