So then what should we focus on? I should take minimal time studying for my histology/neuroscience exam and spend extra time just prepping class V?
Just enough to pass with a good buffer. Practice handskills and execution. Practice talking to patients. Learn material that will be relevant in clinical practice.
Here's some things I can think of, most of dental school was unfortunately useless.
Didactics: Dental materials (probably one of the most important classes but easily the most ignored), pharmacology (most patients are on some meds, you should know what's relevant to dentistry and what isn't, otherwise, you look like a dumba$s in front of your patients if you don't know your meds. Pharm is very important because you shouldn't need to look at guides or anything, it should be hardwired into your system so it doesn't drag your clinical practice down in that you can read a list of meds, know what's relevant and what isn't, and modify treatment execution prn on the fly, not 10 minutes later), minimum thickness requirements for specific dental materials and preparation guidelines + reasons for deviation from ideal, endodontics, perio surgery + implant placement (a primer/how-to), boards. I mention endo/perio/implant as they require some working knowledge of theory in order to start/proceed to clinical and know what the hell you're doing at the very least. Radiology - know what's normal and from there, you can refer everything that doesn't look normal. You can't learn/experiment w/o knowing where to start with those 3. Ortho you'll have to learn on your own most of the time via CE. Some CEs will give student discounts.
Things that don't matter too much to me in practice: opath (just know what's normal, refer abnormal), occlusion(different schools of thought, not relevant since I'm mostly a single tooth specialist), tmd (not touching with a 10 foot pole), most basic sciences unless there's a corresponding applied science that the basic science builds upon, public health/epidemiology/CAMBRA(exception: understand statistical significance of studies), and probably a whole list of other things that have been repressed in the back of my mind.
Clinicals: Endo + extracted teeth (study the canal arrangements, learn to instrument quickly without separation, mount the teeth and know how it feels when a file is about to separate - better it separate on an extracted tooth than a patient, irrigation techniques/protocols, access, and so on), class II's (quick entry and prep) + crown preps + talking to patients + practice evaluating an FMX and treatment planning very quickly (and be able to come up with a few treatment plans + pros/cons of each treatment plan + explain quickly but thoroughly) - there's usually more than one way to treat a problem and you need to know what the patients options are, what your recommendations are, why you're recommending what you're recommending, but taking into consideration what the patient thinks as well (if their priority is time, cost, ideal treatment, non-ideal treatment, and any other relevant input they might throw at you)
Get as much extraction experience as possible - join international humanitarian groups for dental as they are a good way to legally learn exodontia w/o a license. Pretty much go overseas, help a bunch of people, and learn a lot at the same time.
Remember that dental school is just a foundation. You are being trained to be a doctor to be able to evaluate the everchanging landscape of clinical practice, to be able to critically evaluate and understand how things work from a dental perspective. There are underlying principles within each specialty that need to be understood and eventually executed. One example is understanding levers and how it applies to extraction. Another example is understanding tensile/compressive strengths of certain materials and how they pertain to specific areas of the mouth (i.e the forces that a canine undergoes v. molars v. anteriors and what materials work best in certain regions and why). You can go into many layers upon layers of understanding on a specific subject, but you're not getting a PhD, you need to know a broad base of knowledge with a moderate understanding of the subject for potential future application into the clinical aspects of dentistry.
Anyway, this probably all seems disjointed, this is kindof a braindump, hope this helps. This is primarily relevant to those that want to do GP.