I don't really belive in the ominous "burn-in", which is what some people will say is happening here. More likely, burn-in happens between your ears as you get used to a certain headphone's sound.
In your case you may be experiencing something similar. You are used to your DT880 and perceive the T1 as bass-light. Perhaps this changes over time as you get used to the T1.
But in the end, if you're not happy with what you're hearing, the only solution is to get something different. Just take your time - To me, the best things in life are the ones that don't "wow" you immediately. Applies to headphones and to a lot of other things...
Burn in -> agreed. I'm also not a believer.
And that my experiences will change after some more days could happen.
Anyway a few hours ago I ordered a HD800 in addition and next week I will do a comparison with all of my headphones and afterwards I will decide.