Which is better in the long run?
The damage boosting skills: formation, surprise, and explosives are best used when attacking cities or fortresses (or on occasion naval units).
The evasion skills are best used when fighting in the field against other units.
Damage boosting skills are great for attacking units fortunate enough to not hide in a trench, but bad at dealing with entrenched units. Evasion skills are the opposite.
Really I’d say that it is best to have a team where you some generals that are good at one whereas other generals that are good at the other. For example,
Sophia-Isabella
Ney-Lan (or Berthier/Golitsyn)
Victoria-Lannes (Dobeln has bugle)
In this build, sophia is quite good as she is great at accomplishing exactly what the explosives build is supposed to do. When her skills are properly used, there will never be a trench or bunker to block off her damage. However, she is not the best against entrenched units. This is where her sidekick, isabella comes in. Isabella has nowhere near the output sophia has but she can crush the entrenched units with ease.
Really it depends. The ones with the evasion skills are better off used in the field to fight on the battlefields whereas the non evasion generals are better off fighting against cities and fortresses.
It is also worth mentioning that there are both generals that posses both skills and also generals that are meant for other purposes.
For examples, Oudinot, Moreau, Golitsyn, Berthier, Suvorov, Dearborn, Lasalle, Dabrowski, and Radetsky posses both skills. They are much better of being used in the field as they gain a significant advantage over entrenched units.
Otherwise, generals with leadership, defense art, or mass fire are great for soaking up damage. The ones best at this task are Washington and Lannes. They can be used spefically as meat shields, and great ones at that.
All in all, it depends on the circumstance imo. Each general can be used for each type of task (except for Jackson. He sucks).