Frankly, I think there are many more problems than this.
1. I think psychologists/neuropsychologists (at least in the US) are waaaaay too test bound/reliant. One example: There are multiple 200+ page books written about proper WAIS-IV indices interpretation that I have no idea how would would actually meaningful contribute to patient treatment.
2. Clinical exam/interviewing methods are woefully under-trained/under-taught for modern clinical psychologists. A by-product of #1...and likely of current CPT codes.
3. The neurobehavioral exam (think Edith Kaplan and the desert island) is under-utilized and under-trained for most modern clinical psychologists and neuropsychologists. Again, look at our training programs and current CPT codes. And no, I am not pretending to be a House-level physician with this.
4. Reports are too long and talk about "set-shifting." Stick to your audience.
5. Treatment recommendations from psychological and neuropsychological testing reports are often too much, or ironically, too little to be useful in a modal treatment plan. Make it succinct and find a balance.
6. House-Tree-Persons (HTP), Rorschach Inkblot, Thematic Apperception Test (TAT) and other such measures are pretty useless for developing operational/measurable treatment goals/recommendations, although they might be "interesting" to speculate about.
7. "Objective" assessment is not a thing. There really is no such thing. "Our tests" have biases and flaws in much the same way that talking to your brother about you does. Most all neuropsychological/psychological tests (and rating scales) have fairly poor ecological validity as far as I am aware? Relatedly, don't just give rating scales and brief symptoms inventories and tell referring providers this is an "objective assessment" compared to their multiple collateral interviews/information just because these measures have norms.
8. The more tests you give, the more likely you are to find "abnormality" that you think might need treatment/a treatment recommendation. This over-pathologizes and wastes time for clinicians doing treatment.
9. The idea/premise that you need to know every detail about a patient's current symptoms (or their diagnostic origin) prior to initiating treatment with them is complete nonsense, and a relatively recent idea. Psychiatric and neuropsychologic diagnoses were always intended to be flexible and continent upon gaining further information during the course of treatment.
10. Although none of us like to admit it, with some few exceptions, our treatments work best on specific symptoms rather than on the various "diagnoses" we render from our current our manuals/nomenclature.