Let’s break down your argument:
1. The orsis and mosin are pretty much the same snipers when it comes to other snipers on the server. They have similar stats and even though some snipers deal 125 damage as opposed to 100, they are all one shot to the body and head.
2. Yes they do help out your load out, however they should not be as powerful enough to make it seem as though you have to buy them in order to be successful on the server. If I hop on a medic class then my main focus should be literally helping wounded soldiers, not sniping. With the current system it makes it pay to win because you can effectively fill every role that you can on the server: medic, sniper, assault, CQC, etc.
3. The point of donating in the first place is to support Garnet Gaming MRP, then your own personal gain. That is some mysterious concept that not many understand. When you donate, it is implied in the name, you are donating money to help out the server.