I have had two travel trailers with normal spacing between the wheels and my current 2014 trailer with wide spacing between the wheels. To me there is no noticeable difference towing a trailer with wide or normal spacing.
The one big difference I have found and hate about wide spacing between the wheels is if you have a flat tire while traveling down the road. Had a tire go flat on my trailer and the problem is with the wide spacing the good tire won't keep the flat tire or rim off the road. Ended up replacing both the tire and rim ($198.00 for the rim). Never had that problem with my older trailers and I did have two flats them the normal spacing trailers.