Im not totally disagreeing with you, but that concern would have been covered by the 9th and 10th Amendments.
Well, obviously, 9 and 10 come AFTER one, but we are talking about constitutional action, not Congressional Action. 9 and 10 deal with the latter. Remember, these were AMENDMENTS to the constitution. While in some cases they didn't actually amend (i.e. change) anything, they sought to clarify, for example, the bill of rights. What the framers sought to do in the first amendment was prevent the constitution as being interpreted as meaning state establishments of religion (among other things) had to go. Whether Congress came back later and enacted laws dealing with this issue (that would have been covered by the 9th and 10th amendment) was secondary.
Further, redundancy is not exactly scarce in historical Washington D.C. (or New York). I have examples for this, but I think you probably agree with me.