Bigger is not always better. Some geographical locations are known for this way of thinking.
In the same vein, why not get a bigger trailer then, if your tow vehicle can handle it? It really comes down to what works best for each individual.
Not sure at all where you get this idea our smaller vehicles need to "baby" their way up the hill. There have only been two hills I have encountered where it was long and steep enough to warrant slowing a bit. In the past I have mostly towed larger trailers, with larger tow vehicles, all the way up to tractor/trailer combos, and in no way do I feel the my smaller tow is underpowered, or that I am in any way not towing safely.
Not that there is not the odd person who really pushes the limits, wanting to tow at, or beyond, the vehicles rated limits. I am not at all a proponent of this, and discourage it regularly.
I have both a truck (Ford F250 Powerstroke Diesel) that barely notices the trailer behind it, and gets just about as good of mileage towing as does my preferred tow vehicle (Honda Pilot). However (and this is the key), I want a more comfortable vehicle, that works much better as a run around vehicle, gets better mileage when not towing, and is just plain easier to get around in due to its size. I do not want a vehicle that I would use only to tow the trailer.
Once I retire and get rid of my F250, there is a good chance I will still want a pickup, and may get one of the newer offerings much smaller than what I have now, especially if they move towards some good diesel offerings like there seem to be doing now. I might then use this vehicle to tow as well, as it will get lots of use outside of towing too.