To improve gamerUX (gamer experience) for your RPG, you should try to give the gamer lots of things to do (and lots of collectibles too). Below are some elements that could do that for you:
Forging / Alchemy / Cooking
Any of these imply that the gamer can create her own weapons, armor, or items. This allows for an extra layer of customization and a mini-game of sorts.
optional: your game could use 'hidden recipes' - which the gamer could find like she would other items - that teach the player to forge better items.
optional: you could restrict the forging / alchemy / cooking abilities to a particular class e.g alchemist.
Side Quests
This is quite common but needs repeating: aim to make your game as open as possible. Imbue your game with side quests that reward the player.
optional: side quests can be 'chained' i.e. one side quest leading to another e.t.c. Example: Final Fantasy Tactics A2
Collosseum / Games
This is a side quest in which the player enters a competition for rewards. it could give the player battle practice.
optional: you can rank the player and use this ranking to trigger other side quests.
Battle Style Rewards
A lot of RPGs use random battles - and lots of them. It would be nice if the game could reward you for your manner of victory: you gain more experience points if you complete the battle within a certain time limit, for instance. This would prevent the battles from getting boring.
Note: The reward need not be experience points; you could decide to teach the player rare skills this way e.g. the first battle the player completes with 5% health or less could earn the "survivor" skill. This is just an example; I believe you can come up with your own ideas. I'll be willing to help, though.
Threat Guage
I saw this in a game: Skyborn. Here's how it works:
The team shares a guage - each member of a four-man team starts with 25% of the threat guage. Each time a character attacks, he/she gains more of the threat guage. Enemies use the threat guage to determine who to attack i.e. the one with the highest percentage.
This can be used to implement deep battle strategy.
Health/Mana Depletion
This concept is simple: deplete health and/or mana from a player that attacks, depending on the nature of the attack; replenish health and/or mana when a player guards. This should apply to enemies too so you could wear away an enemy by compelling them to attack till they tire.