Hey Kongdej...
Seems like my choices in my hero level up screen are limiting me, mostly by offering stuff I find inappropriate.
So, in order to better that, I suggest these 2 steps:
1) You ask the player to select a category of advancement. Choose a category of advancement out of those 3 choices
a) your current path(s) For example, if you choose warrior, warrior specific (For example ''Lethal'' 1-2-3-4-5) would spawn here.
Magic Rank. Raising magic level would pop up here, so would gaining a new one (for a fee)
c) General and random. For example ''general'' would be like initiative(1-2-3) or resistance or Dodge (1-2-3-4)
For example ''random'' would be: You can now generate free quest in cities (duplicate the quest scroll)
2) THEN you give him his 3 choices (if applicable) in that category.
Maybe 3 choices is too much since you all ready gave him a selection, maybe 2 would be just fine.
------------------------------------------------ thats for Hero level up, above
Now, Armies level up. rather than the bland, generic and flat HP/accuracy increase, provide a choice for the player.
Choices in CIV-5 , as an example, better combat value in flat land (level 1-2-3)... that lead to extra attack, and extra reach
Other choices were: entrench (better combat value while defending), siege: increase city offence...(level 1-2). etc etc.
Refit in Galactic civilization 2 (galciv2) allowed the player the ability to retool its unit(s) for a fee. you could Increase its speed, range, armor of weapon.
Further more, another choice was given in terms of economics. Pay the price now, pay half and the rest in installement, pay in installements.
It was pretty cool.
Anyways, long post for ya 
Be cool