The only real way to prevent "expert players camping" is from preventing acquisition of advanced GBs at all. I don't see that happening outside of a new "special rules" world simply because you'd immediately put a permanent disadvantage on new players.
That being said it depends why these players are finding it a problem as to how much of a solution that'd be. Many of the players I've seen complain the loudest about plundering once a discussion is had with them on how much of the game they understand it turns out they were already struggling with the game in general.
The way to prevent bullying both by age and by city development is to make neighbourhoods based on city starting time. The only things that can make you stronger or weaker than your hoodies then are your activity and your the quality of your gaming.
and money, the guild you're in and your understanding of the game. A player in a top guild could get 2.5k more FPs from their town hall over a year then a player joining a brand new guild (in addition to the other bonuses and resources available)
If players don't mind having the same players in their hood most of the time then it would be a plausible implementation, just might not actually solve anything long term. If you're bundled with a player joining the same day that decides to spend real money, get into a top guild and therefore have the resources to hyper lvl a Arc + other GBs within a short period of time you're still going to have the same problem if they decide to plunder. You're just less likely to get rid of them through neighbourhood rotation if they keep pace with your tech tree. If they camp and then later catch up to you then you're still going to be in the same neighbourhood if it's based on joining times and chances are it'd be a similar situation all over again given they'd have been working on lvl'ing the GBs
I'm thinking your solution would probably be best suited to players stone through to HMA and then from HMA onwards use the current system.