I'm sorry to hear that your experience with the T1s hasn't been more positive. What is really positive is that you've shared your experience here as honest opinions are the most helpful to others looking for information on gear
I get really fed up with Head-Fi threads that turn into a love-in for products, where any slightly contrary opinion is treated with derision. I love my T1s but I never expected to own them. It was only after listening to some other 'holy grail' headphones and finding them nowhere near as much to my liking as other's experience might suggest that I tried the Beyers.
I think with headphones in particular it's important to hear them before buying, or at least be prepared to sell them on if not to taste. I haven't heard the K702s but you have me very interested in them. I have no difficulty believing that I might find them as good as the T1s. The law of diminishing returns is far stronger than a lot of people want to admit. I'm also interested in the T5p for mobile use but as I got the T1s at a very good discount I'm not prepared to pay more than that for the closed version. To tide me over I bought a pair of DT150s for less than £80 new and I'm amazed at how great they sound. When I eventually get the T5p at around eight times the price I know the sonic improvement will be small (although the aesthetic improvement will be immeasurable
)