For example, is it proper for a literary piece to shift verb tenses for dramatic effect? (e.g. from storytelling in a past, omniscient point of view, to a present tense to "pull" the reader into the moment)
Thank you for the opportunity to help you with your question! I'm so glad that I could be able to help you with this today.
Changing verb tenses can be used as a way to bring a dramatic flare to your writing, you just have to make sure that you are using them correctly.
Correct: He was so excited about starting in the football game tonight, Tony could hardly sit still in his seat while he waited for the bell to ring. (Starting: future; Sit: present; ring: present)
Just be careful about how you shift and you should be fine.
Please let me know if you need any clarification. If you would like to send me a quick sample of what you were thinking, I would be more than happy to make sure it is correct. I'm always happy to answer your questions.