ON the one hand, I have to be fairly tolerant of imperfect pronunciation. The idea is not for every student to be perfect, at a native speaker level. I have even had colleagues who were quite bad, though not in my present job. As usual, I think "worse than me = unacceptable." So if I'm not perfect, that's ok, but I wouldn't want to have colleagues a whole lot worse than me.
Still, a significant portion of students in advanced level Spanish courses (junior / senior level, for us 400 and 500] really need improvement. Let's say there will be 5-7 students like this in a class of 20.
What I would like to see is:
--correct accentuation. Everyone is capable of emphasizing one syllable of a word over the rest of them, and learning what syllables that is.
--approximate phonemes. That is, the o of posible doesn't have to be perfect, but it cannot be the o of the English "possible." You should never pronounce u like the u of English umbrella. They don't have that sound in Spanish. Everyone is capable of this too. That is, pronouncing Spanish at least with the closest equivalent phonemes in English.
[Once the phonemes are more or less approximate, then the student can work on improvement.]
--basic ability to read aloud a correctly written Spanish text in a way comprehensible to a native speaker unaccostumed to English. Everyone can do that.
--elimination of English tags: um, like, you know... [when speaking Spanish]
What is needed is:
--Enough input. The students have to have sufficient exposure to good, authentic models.
--Knowledge of spelling conventions of Spanish. Students should know things like: h is silent.
--Knowledge of what phonemes exist and don't.
--Practice reading aloud; auto-critiques of recordings.
A phonetics course is great, but a course can lead to sophisticated knowledge of allophones, regional differences, and many other interesting things, without necessarily improving the student's pronunciation. I don't really care what exact accent the students are striving to emulate, as long as they hit basics common to all dialects of Spanish.
A student should have to produce a tape, to be judged anonymously by a knowledgeable person, at an acceptable level.