You are looking at Relics as something that will never be upgraded again though. The reason why they got rid of the +1 and instead gave them unique names is because relic weapons are something that you can upgrade overtime as the item lv cap increases. Odds are with the next version update we maybe have 100-105 item level, most likely 100 and if that's the case odds are we will be given a new relic quest to complete.

The perks of relic weapons are you will/should be able to continue to upgrade them however, for the allagan, primal weapons and such they are stagnant in their item level and will remain said item level. So while Relics may be replaced at some point if you obtain allagan or prefer the titan weapon, during the next version update that should change and relic weapons will be on par with the latest batch of gear added into the game.