Well 'psyche' is the mind and 'delein' means manifest. The word is a neologism coined in the 50s I think to meet the demand for describing the new experiences people were having in the West with strong drugs, both naturally occuring ones and lab ones - specifically ones in the tryptamine family like dimethyl-tryptamine (DMT). I've forgotten who coined it now. The idea of 'clarity' and thus the visual is deeply associated with the psychedelic, as you point out. As religious experiences have often been associated with visual enlightenemnt as well, there seems to be a close association between a 'psychedelic' state of mind (whether drug induced or not) and one of religious (or meditative) revelation - though many may dispute it.

I thought your description was quite fine, if a little chaotic:-)

http://en.wikipedia.org/wiki/Psychedelic
http://terebess.hu/english/watts3.html