I think its because tactical flash points allow those leveling up a way to group. The older trinity flash points don't pop anymore. There is not enough tanks or whatever to initiate the old runs. After leveling up four guys to the cap, the new tactical flash points have really helped out my experience. However, the problem is there is only one. Running the same tactical over and over again is a bit boring.
Then again, if there was something fun to do with my 55s maybe I would not be lvling so many alts...