Martin uses various tunings other than dadeae,
cgcdgd Orkney tuning is very good,the point is no tuning is perfect,they all [including standard] have different things to offer.
Brian refers to bass resonance ,you get thatTOO with DROP D and Double drop d,double drop d[imo],is a bit more flexible than dadgad,you can play in a easily,and your four middle strings are like standard,so if you finger pick,you can revert back to standard if you want without retuning but just playing the middle four,or get the sound of open tunings by playing all 6 strings.
Julie Henigan has a DADGAD tutor,under the MelBay series,ITS GOOD.