>If you believe in intercessory prayer,
I think this would be the biggest contention for most people. That, and the hail Mary itself as you've laid it out seems to come from butchering other verses; taking out parts from the rest of the verse and their surrounding context and stitching them together as a separate thing. The issue with intercession, for most protestants is, I imagine, as follows:
"You ask your friends and fellow congregants to pray for you and you also pray for them, right?"
>yeah, of course, the Bible tells us to do this
"And the church/congregation is all believers?"
>naturally, my friend goes to a different church and we still pray for eachother
"And-bear with me here- those who have died in Christ are still living in him, as Christ offers us eternal life within him, right?"
>well, sure, scripture tells us as much
"So they're still in the body of Christ, right?"
>of course
"So they could also pray for you?"
>well, scripture doesn't seem to make any clear definitive statement on this one way or another, so I don't know for sure, but it's not outside the realm of possibility
"Well, here's a guy that tradition says is the patron saint of *xyz* that if you have an issue pertaining to *xyz* if you ask him to pray on your behalf, there's a better chance that God will answer your prayer favorably"
>you've lost me