There are many other examples of prayer in the bible, especially John 17. Since we are warned against vain repetitions and since the other prayers are not clones of the "sample" prayer it pretty much shows that we are not to repeat the "sample prayer" as written. That shows that the sample prayer is an outline of topics. What's really interesting is that the Lord warns against verbosity since God already knows what we need before we ask.
All of these things really make vain the idea of asking dead people to pray for us. The is the epitome of vain and repititious. Not to mention there is zero scriptural precedent for it.
If you are a Christian you would not call dead people dead. Saints are in heaven; they have seen God. The bible tells us that the kingdom of heaven inside of us, in our Christian hearts, that God abides in us, and where God is His saints are too.
There is no reason whatsoever why we cannot ask the saints to pray for us. No one is forcing you to do so, but if it is "logic" that drives your statements, there is nothing logical about the faith. In fact, to non-believers it appears rather silly and imagianry.