I use RFC 1345 digraphs in vim to type unicode characteres. In RFC 1234, λ is l* and → is ->. To type the above, I just input l_*x y -_>x+y where _ means backspace. This is easy to learn, fast to type, and covers most of the useful unicode characters.
A shame, too. At least decent editors make this a tad easier. DrRacket, for example, binds lambda to Ctrl+\. Racket accepts both "lambda" and "λ" as the same thing, so it's up to personal preference.
I'm well aware of how DrRacket works; nonetheless, telling a newbie to type "lambda" will lead to typing, and telling them to type a lambda will lead to griping.
Also, the difficulty of typing lambdas also means that writing blogs about code, or documents, or emails, will require even more pain.