I am not only talking about people who manages to use a very colorful language, but someone who also uses a large variety of syntax, idioms, figures of speech, obscure grammar rules, etc, as if they wanted to put everything they knew about a particular language in the text they write. Is there a particular word for this? I am thinking there isn't a particular words for this, but a set of words that are required to describe such a text or person.
Lexicological perhaps? It's the adjective form of Lexicology, which is the study of words and their usages. Syntax and obscure rules don't really fit, however.
Descriptions that come to mind are that the text is pretentious or showy and that the author is showing off.
The memorable name Engfish for bad writing comes from an article by Ken Macrorie in his book Telling Writing.
One day a college student stopped a professor in the hall and said, "I have this terrible instructor who says I can't write. Therefore, I shouldn't teach English. He really grinds me. In another class I've been reading James Joyce, so I wrote this little comment on the instructor in Joyce's style. Do you think I should submit it to The Review?" The professor looked at the lines she had written about her instructor:
… the stridents in his glass lisdyke him immersely. Day each that we tumble into the glass he sez to mee, "Eets too badly that you someday fright preach Engfish."
and he knew the girl had found a name for the phony, pretentious language of the schools—Engfish.
Most English teachers have been trained to correct students' writing, not to read it; so they put down those bloody correction marks in the margins. When the students see them, they think they mean the teacher doesn't care what students write, only how they punctuate and spell. So they give him Engfish. He calls the assignments by their traditional names—themes. The students know theme writers seldom put down anything that counts for them. No one outside school ever writes anything called themes. Apparently they are teacher's exercises, not really a kind of communication.