>>26765587Some replayability value, definitely. That can be achieved in several flavors. For that, it's vital that the game has two or three save files.
1. A New Game Plus which keeps your Pokemon from the previous playthrough in a set of boxes.
All Gym Leaders will approach you with a full team of 6 fully evolved, level 100 Pokemon (and douche strategies now that we're on it). Road trainers will approach you with Pokemon in level 80 or more; and items like Mega Stones and legendaries obtainable only in New Game Plus.
2. Optional sidequests to earn nice items. Some sidequests render others impossible to do, so you'll have to beat the game at least twice to discover all the secrets.
3. Make your starter Pokemon choice to impact the gameplay deeply. A quick way to do that (I figure) is blocking different routes after a hub in early game (after the first city, let's say) using HM obstacles. Each one of your starters will be able to learn only one of those HM moves, forcing you to choose a different route if you choose a different starter.
For example, imagine that Rowlet can learn cut, Litten can learn Strength and Popplio can learn Surf; and no early game Pokemon can learn those moves.
After the hub, you have three options: a route blocked by a pond (only accessible by using Surf with Popplio), a route blocked by a little tree (only accessible by using Cut with Rowlet) and a route blocked by a boulder (only accessible by using Strength with Litten)