I haven't commented on the issue yet, but I feel that I have to...to hang on to old guidelines that so poorly inform the very students that we're trying to help.
To say that there is a future tense in English, formed with "will" (let alone "shall", as riverkid correctly mentioned), creates such erroneous (and unfortunately very solid) beliefs regarding the use of modals and tenses, that it takes a lot of hard work to alter.
Someone asked me today, why do we use the future tense in the example
-The bell is ringing.
-That will be the postman
It wasn't easy for the person to understand that this isn't really referring to the future...