Yeah, I must agree with Stuey...if every weapon can be customized to ones liking from any mod then you wouldn't even need to find a good weapon...only would need a clean rare item and just mod it up to ones liking...so hopefully they don't add that feature.
errr....if shield mod become changable...then it will piss me off too.....btw 15^50mod may become a rare mod and the price will be very high. :/
but in my sense...actually Anet is going to crush the GW economy and increase the chance for the less wealthy players to obtain perfect weapons....this would piss me off too...coz after i have done the missions, the reasons for me to log in is to chat with my friends, trading and make some money....lol