On the side of caution
As for overkill, there may be a few with a bit more tow vehicle than absolutely required, but by and large, not only the members of this forum, but most A/Sers are towing with largely compatable vehicles. While it may seem that tow vehicles have become the latest "mine is bigger than yours" toy, the reality is that the large diesel engines are more economical for the full-timers and they offer tremendous torque which really is nice when pulling mountain passes. Until recently, most A/Sers were towing 27-34' models and with the current generation of A/Ss having gained more than just a little weight, the only adequate tow vehicle available has been a big truck or van with a huge V8 or diesel. As the smaller A/Ss are regaining popularity, new tow vehicle options are emerging. What is scary is that many new comers to towing are not aware of the physics involved and lack good rule of thumb guidelines. The compact SUVs are poor choices for tow vehicles, not because of engine or tow ratings, but because of short wheelbases. You really need at least 120" of wheelbase to be safe with the shorter A/Ss and around 130" or more for the longer A/Ss. As long as those using larger tow vehicles avoid allowing overconfidence to set in, a larger tow vehicle is a positive factor, while even the best driver can't overcome an inadequate or inproperly setup rig.
BTW, you mentioned that your A/S does not have electric brakes. Does that mean, no brakes period, or does your vintage beauty have hydraulic surge brakes? If you are lacking any kind of trailer braking, you are breaking the law in virtually every state and risking yourself, your rig and those around you. While it varies from state to state, most states require brakes for trailers over 3000#. Some are lower, like CA at 1500# and a few like Alaska are higher at 5000#. Understand that your Tacoma brakes were not designed to stop an RV and the truck. Also trailer brakes keep the trailer pulling against the hitch during panic stops, which keeps it in a straight line behind the tow vehicle. You can also engage the trailer brakes with the controller to stop sway. Without brakes the natural tendency of any trailer in such a situation is to keep going and that means, it most likely will try to pass the rig towing it (jacknife) and total loss of control.
Towing is not rocket science, but it is not seat-of-the pants either.
david & bret
'02 Bambi LS
'99 34' Limited
Air Forums # 2159
Past President Heart of Texas Camping Unit
WBCCI # 7548