Cavalry expert vs surprise attack

I think this has a lot to do with the role you assign to each of your cavalry generals. Of course, it also depends on the unit used. For example, Armored Cars can't cross mountains even with mountain fighting. Moltke, if used on breastplate cav to flank, grab cities and to attack enemies from undefended angles will profit from Mountain fighting + Jungle fighting + Surprise.
For me, mobility is very important, so Jungle fighting is a must. Tactic Master is a 1.20 damage multiplier and generals with high battle and unit ability (and the best items) make the most of it. It also allows me to spread the damage to different targets. Precision strike is a bonus in every situation even if it becomes less relevant with higher unit base damage.
One should also consider how much books are needed to change a skill vs. how big of a benefit is gained through the skill change. For example changing Edge to Surprise on Jackson (2 skills have already been swapped) for 15 books - well, I wouldn't prioritize that.