So you could have an assault with sprinter or a heavy with deep pockets. After a soldier receives a class and their first ability, additional ranks can grant randomized abilities from a pool of the all the class abilities sets minus any skills that are dependent on a specific weapons (which are still class locked).
However, i can confirm that training roulette can be fun - deep pockets stacks with grenadier (each pile of grenades is 3 deep). Each soldiers training tree is mostly randomly generated. Training roulette is a second wave option introduced in xcom enemy within.
Not only does it do exactly what it says on the tin, randomizing skills for greater replay value, it makes each member of your team completely unique which adds a ton of attachment to each member of your squad. Training roulette greatest option ever seriously, if you havent given the training roulette option a try yet youre missing out.
