Thanks for your question! I think your instincts are correct! The evidence still supports patching as directed by your attending Ophthalmologist, and perhaps convergence exercises (aka Pencil push-ups, if there is an element of convergence insufficiency in the intermittent exotropia).
Your Ophthalmologist would have evaluated your child to exclude a secondary cause for the exotropia, and would be working with you to optimise her final visual acuity and alignment in order to maintain excellent visual acuity and binocular vision.
At some stage as she gets older, your Ophthalmologist may suggest the option of strabismus surgery to assist your child in consistent alignment of her eyes in order to maintain binocular stereopsis throughout the day.
Vision therapy as you described it, is best reserved for once you are successfully patching your childs' eye as instructed by your ophthalmologist (and performing alignment exercises as directed), and if you have a surplus of time and energy with excess financial resources.
ESG