They all revolve around the same plot. Evil men/corporation/group is introduced in the opening with forshadowing plot, queue opening theme of movie, ash and friends forget around when they hear word of a mysterious pokemon, they investigate, find out what bad guys are doing, want to stop, somehow ally themselves with ultra powerful pokemon or some stuff, bad guys get beat and they go on there way like nothing loving happened.
The only one i think i ever liked was Destiny Deoxys. Except this time it was a Pokemon attacking everything instead of an evil corporation.