There's something called 発声練習 in Japanese that アナウンサー use to perfect their elocution, and I think it'd have a lot of merit if you were aiming to achieve native-level pron (see here for the general idea). There are even exercises that involve putting weights on your cheeks to nail い. I don't think I've heard anyone except my linguist friend stress the importance of enunciating vowels correctly. Most learners seem to think they're "basically the same as English," which means they're pretty much guaranteed to sound "un-Japanese".
I don't know how much I value the idea of perfect pron, but I find it interesting learning/practising some basic phonology, just like I found kanji, grammar, vocab etc interesting to varying degrees. You don't hear many people downplaying their significance, but pronunciation seems to be something of a punch bag. Pitch seems to take the bulk of the blows because it can be so seemingly insignificant if you're unaware of it, which most of us are at the beginning, and potentially for a very long time.
I don't know how much I value the idea of perfect pron, but I find it interesting learning/practising some basic phonology, just like I found kanji, grammar, vocab etc interesting to varying degrees. You don't hear many people downplaying their significance, but pronunciation seems to be something of a punch bag. Pitch seems to take the bulk of the blows because it can be so seemingly insignificant if you're unaware of it, which most of us are at the beginning, and potentially for a very long time.

Any feedback on their effectiveness?