Transaction fees should be the cost to store the data and has nothing to do with the amount being transferred.
Anonymity coins need artificially and excessively high fees in order to prevent spamming the anonymity sets as a way to unmask the anonymity.
Thus anonymity coins need to reveal the amount of the fees.
If noone is doing any transactions then the coin is dead. The percentage of the transaction taken in fees needs to account for the storage of the data etc.
Another way to overcome this that would be acceptable to me is a small "tax" on holdings that goes to miners, ie, every 3 days the equivalent of 3% per year gets removed from wallets and given to miners or something like that, although that may not work because it would make millions of transactions that would need to be processed so maybe I didnt think that through....
I dont mind the bitcoin fee system (the user sets the fee they are willing to fee, the lower the fee the longer their transaction will take), in fact I would probably be just as happy with that fee structure as a percentage structure.