Sloping is most useful on the front of the hull and turret, as that's where one wants the most protection. On the sides with less protection the tradeoff wrt internal hull volume probably isn't worth it.
As for transport, I do wonder about the mobility of the Tiger and other heavy tanks of the era. Today with trucks pushing 40 tons and in some cases more, the road infrastructure and bridges can most likely take a 60 ton tank. But in WWII a big truck was what, maybe 10 tons, so the 55 ton Tiger was absolutely gargantuan in comparison. How many road bridges in WWII Europe was able to take that kind of weight?
Fording capability was a requirement for the larger German tanks due precisely to the problems with a large number of bridges due
to the weight as you pointed out.
The British answer which was adopted by the US was the bailey bridge. The modular parts design kept the weight down and allowed
manual handling during construction as well as different configurations according to weight requirements. The Bailey bridge was a very
important development for the Allies and is said to have saved a lot of lives (crossing rivers can be dangerous and supplies must keep
coming once you are across).
The Bailey was used very effectively in Italy where in a 20-month period US and British armies constructed more than 3,000 fixed Bailey bridges.
The combined lengths of these bridges was 55 miles, with an average length of 100 feet.
Bailey panels could also be used as piers for larger bridges. One bridge was over 1100 feet long. The Bailey was adaptable to become part of a
suspension bridge. One built over the Volturno river transported 240,000 vehicles in eight months.
US and British logistics were a major strength compared to Germany.