A lot of good points about how the mere mention of Champions, Wardens, Loremasters etc. may not reflect the class but are book basis for the naming of the game class.
Also, a general contempt for the Rune Keeper class as not being canon, creates an atmosphere where people ignore some important information from the books:
While the "Rune Keeper" indeed uses runes carved into stone etc. (class quest on Amon Sul) it's clearly a different meaning here.Daeron:
An Elf of Doriath who created the Alphabet of Daeron. Daeron was a Sindarin Elf. The chief loremaster and minstrel of King Thingol, and he was considered to be the greatest singer among the Elves.
Daeron developed his alphabet by 1300 of the Years of the Trees, and around 1350 he made revisions and improvements. The Alphabet of Daeron - or Certhas Daeron - was a system of writing with runes to represent the sounds of the Sindarin language. The runes - or Cirth - were angular letters that were suitable for carving into stone or wood.
Again speaking more of Runes as a written language than words of power. But the mention of Runes and the connection to the Elves and Dwarves might explain why the class was limited to those races. I can see why people feel there is no book basis for the class but the title certainly makes sense given the history of Runes with that of the Elves and Dwarves.Celebrimbor:
Celebrimbor befriended the Dwarves of Khazad-dum, and they shared skills and secrets with each other. The Dwarves adapted the rune system of the Elves for their own use, while Celebrimbor became highly skilled in working with mithril.
Celebrimbor is most commonly known as the son of Curufin and grandson of Feanor. In one version of the story, he was described as a Noldorin craftsman who worked for Turgon in Gondolin. In another version Celebrimbor was said to be a Sindarin Elf who was descended from Daeron, the originator of the runes used by the Elves.
Essentially, the only true classes would seem to be Hunter and Burglar. Perhaps Captain (even though Captain is probably stretching the definition when looking at the abilities of the class)
Wardens, Champions, Lore-masters and Minstrels seem more to be titles than actual definitions. Although it could be argued that Minstrel truly means musician/performer and is more than just a title ... but again the class abilities are exaggerated to make the team dynamic work. In my opinion, Guardian seems to be the title they stretched the most.