the way they did expansions in wow wasnt the absolute worst way possible sure it wasnt anywhere near the best way to do it but it worked, well in my experience with my guild anyways. sure the old gear becomes obsolete thats what happens when you level up new gear comes along and old gear gets dropped, but people seem to forget that this is swtor where in a lot of cases the mods make up the gear not the item itself, if you like a way a piece of gear looks you can just replace the mods with the mods from the new gear, granted this doesnt apply to gear sets. and the argument on ops never being played again would be to add something similar to guild achievements that reward a guild for running the old raids
the way i see it is: if you werent upset that the gear you got from a lvl 10 heroic was obsolete at lvl 20 you shouldnt be upset that the gear you got at 50 is obsolete at 60