Poorly maintained roads because people do things like travel to the woods to go camping and they will drive over some rather poorly maintained roads to get there. Also, adaptive steering will be a good start but I have no expectations of it being absolute. I would not be surprised to find a better constructed idiot (though I do not expect most people to know) attempting to drive with a trailer.
That said, again, I think this is an excellent idea and have even mentioned it myself in the past. It is just that it is not going to be perfect. That is okay too - it does not have to be perfect. It just has to help mitigate certain aspects - like range. I just think we need to be aware of the problems and work on those as well and adaptive steering is one such thing that can help. I would like to see it include things like tire pressure monitoring, additional reverse camera(s), a high level (commonly called a third) brake light, and more. I think it should be something you can disconnect from the vehicle, when you get to your destination, and used as a generator as well as a then-static EV charging platform. It would be great for camping and great for emergencies. Even better would be some sort of open standard that automatically tripped the mains breaker so it could be used as a house feed without worrying about pushing the power out onto the grid.
Anyhow, do not mistake me for someone who is binary on such things. I would prefer a blended solution where things like this are discussed and realistically debated. There will be some risks added with people lugging trailers behind them and that is okay - we can lower the odds by making things risk adverse but we can not lower the odds if we do not look into them. We simply can not say that this one solution will be adequate, wipe our hands off, and be done.
I drive. I drive a lot. It is not uncommon for me to do stuff like just head out and randomly pick a highway and go to a different state, get off on the first exit, and just go where the road takes me. I see so many folks who should not be allowed a license. Two of the worst offenders are people with trailers and people with snowplows on their private vehicles. (Even some professional plowing is done by rather inept people.) I do not have a solution for either of those two things and I have thought about it. Unfortunately I think increased regulation, perhaps some sort of tiered license, might be in order but I am rather loathe to propose it without more thought.
My current thinking (subject to change) is that we could absorb the overhead and make them like motorcycle licenses are treated in many states meaning that it is not a separate license but an extra certification that enables one to lawfully operate a motorcycle. There are drawbacks to that idea but many of them can be waived away simply by pointing out that driving isn't a right but a privilege and the commons must be protected for the good. Even still, I am not a huge fan of this. I think that a program such as this could already be in effect - regardless of the EV future and that these extra privileges should be inexpensive and easy in regards to the act of getting them but not easy in regards to earning them. In other words, the paperwork and process should be easy. Making them easy to get otherwise defeats the point so the educational process should be well done, inexpensive or perhaps even free, and so on.
Driving with a trailer requires a whole new level of attention to do properly. It requires skills that people do not have. Adaptive steering is going to help on vehicles that are equipped with it. I would prefer to mandate education than to mandate a technological solution for reasons that should be obvious. I am not opposed to this trailer idea, indeed I have mentioned its benefits in the past, but I think we need to be aware and honest about the risks involved and figure out how to work within those constraints to make things as safe as is reasonably possible. The vast increase of people hauling trailers around is going to be a hazard, I am certain of this. No technology is going to solve this - humans are involved. No, that does not mean that I think we should skip this idea. It means that I think we should examine this idea and weight the consequences and do what we can to lower the increased risks this will cause.
By the way... I would love something like this for my RV (and it would be awesome to have an EV RV [ERV perhaps?]) but I often tow a car behind my RV so that I can more efficiently and easily drive into a city or drive to other areas from a central location. I can drive with two water bowls behind a deuce and a half but this would a difficult configuration with an RV. One of the ideas that I have had is to work on making this not a trailer. I have seen storage capacity added to a vehicle by attaching a rack to the trailer hitch. It may be possible, safer, to simply engineer a method that allows carrying this generator behind the vehicle without it actually being towed. I suspect that would be safer though I am not certain it would be more efficient. It would also likely require that it be engineered into the vehicle as that may be a lot of weight to be on a traditional trailer hitch for most vehicles but that is a trivial matter.