I have read several of these post of people who are downing the use of tow dollies and I'm pretty sure I know what you are doing.
First, tow dollies as are trailer axels are made with a certain amount of caster and toe-in so it will self center after a turn same as a car. If your receiver is not the proper height it won't track straight.
Second, If your straps get loose, you didn't put them on properly. I may have to add a click to the strap ratchet but not often.
Third, How do you hook up your 4 down in the rain? The tow bar pins, the safety cables, the light wire, how long do you have to idle and run through the gears to oil the trans? How often do you stop to do this? Did you pull the fuse? Install brake controller? Must be Magic.
Fourth, I can back my dolly and car just as far as you can your 4 down.
Finally, DW and I can load our car and strap it less than 10min. and unload it in 2min.
If you decide to go with a tow dolly, get a good one It will be cheaper than having nice car butchered to install tow hooks and having to buy a brake controller.
Sorry I had to vent.