Items don't get better, which we can clearly tell by people using the same weapons from VoG almost a year later. You're also asking us to gamble on TTK with the small chance that there will be a new weapon we might like, rather than go with the sure thing of letting us simply use new weapons if we like them and ascend old weapons if we don't. Making old gear obsolete does nothing but give us fewer options, and is bad for the players no matter how you try to spin it.