I've used most of the range of Nikon cameras from the D40 up to the D700, which is currently my go-to camera and both AF-D/AF-S and manual focus versions of macro lenses.
For macro, I've found that it's often difficult for the camera to intuit what subject that I'm interested on snapping of picture i.e. is it the shrimp, the leaf behind the shrimp, the rock the shrimp is on? What it comes down to is not a matter of how fast it finds focus, but how fast it finds the focus on the right object, which is complicated even more by the narrow depth of field of macro photography.
Expecting a camera to find the "right" object among a group of objects is like asking it to read our mind. Of course, that will fail most of the time.
But it is very easy and simple to deal with your issue. Just set your camera's AF-area mode to "single-point AF". That means you will select a focus point manually and your camera will do autofocus on the subject in the selected focus point.
On a D90 with only 11 focus points, I have no problem focusing on a shrimp surrounded by java moss. Your D700 has 51 focus points - five times that of D90. Therefore, setting the proper focus point on your camera is like a piece of cake. May I suggest that you learn to use your camera's autofocus system. That will help you to appreciate AF-S. It is like some people who insisted on shooting manual exposure with their modern day Nikon until they learned of the CLS in their camera.
It takes a bit of practice, but it's well worth the investment. Especially given the fact that AF-S lenses are often 5-10x the cost of their manual focus counterparts and way bulkier to boot.
In autofocus mode, your camera uses the many tiny pixels inside the chosen focus point to do focus. There is just no way you can get a more precise focus with your eye through the view finder.
Also, when shooting in autofocus mode your camera has a safeguard to ensure that the area that you focus on is indeed in sharp focus. It won't release the shutter when the focus is even a tiny bit off (of course there is a way to override that safeguard).
But when shooting in manual focus mode, there is no such safeguard. Therefore, within the view finder's low magnification, you think you are in sharp focus but in fact you are not. You won't find that out until afterward. But by then the shrimp that you were focusing on probably had moved and you had just wasted a precious opportunity.
As to being more bulky, if you have to hold the camera steady for some time in order to get the focus right, yes being bulky hurts. But when the focus is instant and spot-on, bulky or not matters much less.
In fact, when shooting macro with an AF-S lens, I seldom used a tripod. And it is not unusual for me to have just one hand holding the camera and lens. Yet I kept getting sharp focus with magnification approaching 1:1 and beyond.
The purchase price of my entire manual focus lens kit combined is less than the cost of a single one of my AF-S lenses.
Isn't that astounding that an AF-S lens can command such a price premium? But there is a very good reason - the lens' precise speedy focus.
The world does not stop and wait until we get a sharp focus.