thenooblet22, I'm not trying to put words in your mouth. I'm saying that having a system of leader traits that will make it hard to impossible to plan long-term is no fun, and therefore (to me at least) pointless. One of the reasons I like Civ4 is that the leader traits give me an advantage over other civs, and if I plan well, I can use that advantage while keeping other civs from using their advantages that they have over me.
This doesn't constrain me to one path, as you seem to think. I can be an aggressive ruler, for example, and use that to help me have shorter, more successful wars so that I can get back to building sooner. I don't have to warmonger, but to use the trait effectively I do have to plan. It would be extremely annoying to prepare my troops to take a single key city and then DoW only to have my aggressive bonus disappear the next turn due to succession. Sure, I could go to war with enough units to guarantee victory in the event that that happens, but then I'm not using the aggressive trait to my advantage; I'm ignoring it.
Leader bonuses that are powerful enough that you can't simply ignore are bonuses that require planning to make best use of them. If you keep changing the bonuses, you hobble the player's ability to make and execute a plan, which makes for a frustrating game-playing experience.