They're not obsolete. They're being phased out just as you put it. The campaign starts at about Level 25 or something around there. Your Year 1 weapons are more than ready for the start of the expansion, but there's new loot to be found during the campaign.

I'm only going to say this one more time What level are you? 34? Wrong, you're level 20, your gear artificially raises your level to 34 but you're still level 20 What level are your weapons? 34? Wrong check the level requirement on all your gear, weapons and armor, all level 20 Why doesn't your level 30 armor perform well against level 34 enemies? Because it drops your level The armor that kicks you up to 34 though is great Because it scales damage AS IF you were level 34 It's still level 20 gear Think back to your first blue gear Level 10-15 probably It was probably the best gear you had for a long time even with gear outclassing the armor or defense rating You probably held onto it for about 5 levels before you found a green that was better Don't dismantle everything when TTK releases because I'm sure your level 20 gear, the same level 20 gear you've been using at level 34, will still be effective [i]at least[/i] until level 34 And you may replace some things But that's only because they will be [i]better[/i] than what you currently have I'm not seeing a problem here Bungie literally only told us we would find gear with better attack and defense ratings off the bat That doesn't mean our current gear will be useless immediately That means that we 1) will have more options right off the bat and 2) can expect gear that kicks our current gear in the ass by the time we hit 40 Also RNG is getting tweaked so the game will take all your gear into account for drops And if you have all your purples still won't that increase your chances of finding better guns? I just don't get why everyone is so up in arms about this I'm done Your guns will be obsolete, yes, not suddenly paperweights