I have never operated a tow vehicle and trailer with a front-mounted hitch, but I have moved small boat trailers on level ground just by pushing them from the tongue.
I can see there will be two advantages to using a front-mounted hitch compared to the standard rear-mounted hitch:
- the driver will be looking forward at the trailer and can more easily see the trailer's movements compared to looking at them in a mirror which distorts the left-right orientation, and
- the much shorter distance between the hitch and the front axle will create much faster left-right movement of the hitch as the front wheels are turned, allowing much faster correction and control of the trailer movement.
One drawback I see is the loss of weight on the rear wheels of the towing vehicle created by the ramp slope. If you are launching with a rear-wheel-drive-only vehicle, the weight on the rear axle will be reduced by the front-hitch load and by the downward slope on the ramp. This could cause a problem with tire traction on a wet or slippery ramp.
Also, pulling a boat up the launch ramp with a front-mounted hitch will reverse the situation, and to steer the truck in reverse may become a bit awkward if the ramp has an immediate turn to be negotiated. In my experience there are many launching ramps that require executing a turn at the top of the ramp due to limited area.
Finally, there is no way to haul the boat on the highway with a front-mounted hitch, so the towing vehicle will still need a rear-mounted hitch. The trailer must be unhitched, the towing vehicle turned around, and the trailer connected to the alternative hitch. This process would need to be done twice for each trip to the launch ramp, and in my view the process would become tedious, particularly if the launching and recovery of the boat were being done routinely.
I cannot recall seeing anyone at a launch ramp use a front-mounted hitch. I would expect that the most useful application of a front-mounted hitch would be at a boat trailer storage yard where the yard operator moved the trailer from a storage area to a parking area for the customer to pick up.
A peripheral concern is the appearance of the towing vehicle with a front-mounted hitch and possible effect on the value. I would be quite reluctant to buy a used truck with a front mounted hitch.
Overall, I do not see much advantage to having a front-mounted hitch for towing a boat trailer as might be done by the typical trailer boater.