Here is some commentary regarding the passage you refer to in (Romans 6:3-4):
"So although baptism is not a means by which we enter into a vital relationship with Jesus Christ, it is closely associated with faith." (The NIV Study Bible, copyright 1995, pg. 1715).
But that is not all it says. One of the first rules to conclusive bible study is to take in ALL that the bible says regarding a specific topic. That too would apply to commentary which has been referrenced.
In this same NIV Study Bible, same page, further comment reads: "In NT times baptism so closely followed conversion that the two were considered part of one event (see Acts 2:38). Baptism depicts graphically what happens as a result of the Christian's union with Christ, which comes through faith...As we fell into sin and became subject to death in Adam, so we have now have died and been raised again with Christ-which baptism symbolizes."
Now, considering such a slight distinction between faith and baptism, (if one can be drawn at all), would anyone who truely loves the Lord and who wants to do everything he can to be Christ-like, dismiss baptism with the mere "assumption" it isn't necessary to salvation?
I don't think a true, sincere Christian would do so!