will be any way in the future that you can reuse an address you have spend on?

lets say you get donations for dogs at addres "AKWAN99"
and after lotof donations, you must use the money to buy things for dogs, so you do a spend transaction, the address "AKWAN99"
with this action just filtered part of the private key, so they do not recommend to spend twice on it as you will make public more and more the private key on AKWAN99,

okey, so you must now change the address in the website so you get a fresh unused address,

but what if some people who dont know the change, saved the address and keep sending coins to AKWAN99?
you can't stop them, but they force you to spend again to move out the money, making the private key even more vulnerable,

and so on, and so on,

thats the single point of IOTA that might return a bit of problems, as in any alt-coin, paypal, bank account, anything... you can have a static payment address where you can spend and use, move, and so on,  and with IOTA it becomes more strange, you can't tell people to always "donate there"
maybe some one want to donate, lets say 100 kiota every month, they can't stick to an address and do always the same move like with any other system,

is there any way to solve this little issue? or by design is something impossible to change and will always be like that