5770XW1 is what gives you the capability to connect to your IBM i using
the IBM supplied telnet programs and other things that check the
5770XE1 is only there to store a copy of the deprecated client on the
server for central distribution, updates and whatnot. Basically the stuff
for "Check Service Level" if you have your service directory set to a
share on IBM i. (Like who can get "Check Service Level" to work for the
masses anyway on newer versions of Windows?)
So, does it make any sense to leave 5770XE1 on your IBM i anymore?