One could make an argument that the person with 5000 hours at the same small animal clinic and nothing else has less perspective into the veterinary profession than someone with 50 hours in each of equine, food animal, small and research.
In short, even bypassing tech school but still planning on getting a job as a tech/assistant/whatever after school at a clinic could be a waste of time and resources. Instead, volunteer on the weekends or on school breaks with different vets in different fields.
This is thoroughly going to be dependent upon which school is applied to as well. Some schools like to see that breadth and others like to see depth. Also, no school is going to think 50 hours in each of equine, food animal, small and research is a lot of experience or gives that person a great view on the profession. That is equal to working one week in each area. Just about every school would like to see depth in at least one area (over 200 hours I would say is a minimum, but 500 hours is more on line with average). I am not saying you can't get accepted if you have less experience or only 50 hours in each area, it is just really not that great of a number of hours unless you have a stellar GPA to back it up. If you are applying to somewhere like UPenn, having just 100 hours here and there will not impress them, but some other schools may appreciate that. You have to balance out what you have done and experiences you have obtained with which schools you apply to. If you have a lot of depth of experience, apply to places that like to see depth; if you have more breadth, apply to places that like breadth.
I also disagree with the poster saying that being a vet assistant is similar to being a physician's assistant.... that is a laughable comparison. A physician's assistant has gone through school and can even write some prescriptions.... a veterinary assistant does not come close in comparison. Just because they both end with assistant does not make them equal. I don't think tech school is a good idea for someone who wants to be a vet, in the end. Just gives you more debt. Working in a clinic can give you a good insight into the profession and how to relate to techs/assistants/receptionists/etc. If you are going to work in a specific area of vet med though, it would be wise of you to do as 2CatMatt was saying, and try to shadow/volunteer once or twice a week in a different area or aspect of vet med. I don't agree that having 5000 hours in just one area of vet med gives you any less perspective to the profession. I had easily 10,000 hours in small animal med when I was accepted. I knew about the other aspects of vet med and made an attempt to research them/know some current issues in those areas and made an attempt to get a few hours seeing them (though that didn't work out as well). I am not the brightest when it comes to horses/cows/sheep/etc, but I have learned fast.
The other thing that working in a clinic does that volunteering or shadowing does not provide you (generally, since most shadowing gigs don't allow for client interaction) is how to properly communicate with clients and how to build that relationship. Good communication is one of the best things that you can learn and if you can begin to get this down before vet school starts, it is a huge bonus. Going to a school where most of the students are young kids out of high school (with minimal or zero experience) and doing communication labs where a client from the teaching hospital volunteers to come in and acts out a scenario, you can see that these kids really are unsure of themselves and do not know where to start/what to ask/or how to begin a conversation with a client. It will be a learning process for them, they will get it down with experience and time, but having that experience before school, is really beneficial.