I'd be interested to hear your thoughts if you do end up comparing the T5p with the D7k. I've never heard the Denons myself, but judging solely based on reputation, I'd be surprised if they were on the same level. But again, this is based on the opinions of others, so it would be intriguing to hear the thoughts of somebody with both sets handy to compare.
I have the impression that many underestimate amplification for Denon AH-Dx000. Yes, they're sensitive, but they need amplifier control. Some amplifiers succeed, others don't. Grace Design m903 does a very good job.
I've read quiet a bit about Denon AH-D7000 and AH-D5000, and heard both. I can relate to some of it, typically the ones I believe have used them with good, well suited amplification, but I have often thought that this or that person haven't heard the headphone well amplified and hence at its best, or he's playing at very high loudness levels or something else you shouldn't do.