There certainly are words that had much more impact in the past, which are still around today and people don't really think about. This includes some very mild interjections, even childish ones, which once were the subject of public censorship and official disapproval. An example of this is "Zounds" - certainly not offensive to anybody today, and almost comical in many uses. It derives from "S'wounds" which is itself an elision of "God's Wounds." This was considered quite profane, and was censored by the government in scripts for plays and the like, in the Elizabethan era. (An example of this, with discussion, can be found in Charles Hamilton's "Cardenio or the Second Maiden's Tragedy.") The interjection "byrlakin!" (which I know is a bit obscure, at least in the US) is another example - it derives from "by our lady kin," an oath in the name of the Virgin Mary. In my experience, at least, it is largely religious references that have lost some of their impact. The actual "words you can't say on TV," so to speak, have largely been in use with minimal alteration for many hundreds of years.

The real fun comes in slang, which changes far more quickly than profanity. For example, "Abbess" to mean the madam of a brothel, or "proud" to mean horny. These might not be considered "bad words" but they certainly weren't for polite company. The "1811 Dictionary of the Vulgar Tongue," available free online from Gutenberg provides countless examples of this far wider category.

I'd also suggest checking out Holy Sh*t: A Brief History of Swearing, if you're interested in going in depth on the topic.