I also think that (and I'm saying this as a 4 x 4 for at least 28 years! ) some of the 4 x 4 lose some of their power compared to a lighter car ie when we chose our 2.5ltr Shogun in 1991 we knew we would be using it to tow a large Burstner, with a weight of 1500kgs, the Shogun was close on 2 1/4 tons, so used quite a lot of motive power just to get it rolling, the modern diesels are more powerful and used in ever lighter cars, so weight of the tug needs to be considered.
But then wheelbase comes into it as well, shorter tugs can be susceptible to pitching (usually due to bad loading) whereas a lwb tug is less so. With a 4 x 4 it is usually possible to see through the towed vehicle due to being sat at a greater height, which I used to find really helpful.
A 4 x 4 gives comfort to some but in 20 years of having the Shogun it went in 4wd twice! Once when new as part of the handover checks and the same the day we sold it, the Rav did'nt let you know when it switched between 2 or 4wd so ghat might have been more frequent?
There are so many choices and differing criteria for each user, at the end of the day I'm sure you will be happy with your educated choice