I blow hot and cold on the notion of mythical Pokemon being directly given to the player rather than captured by them - sometimes certain species suit having a different OT and ID number, like Genesect having "Plasma" as its OT or Marshadow having "Mt. Tensei" as its OT as a nod to that one movie and as a way of representing a location that doesn't exist in the games.*
If I am forced to have a certain Pokemon under a fixed OT though, the least I ask is that it be a cool name and not something lame like OCT2014 or MYTHICAL22. Even if it's something relatively simple like "JUNGLE" for Zarude or something a bit more abstract, like "ALAMOS" for that one Darkrai. Even regular names are better than nothing (ex: Diancie being given out with the OT "Hope", Hoopa being given out with the OTs "Manesh", "Harry", and Alexander", and Volcanion being given out with the OT "Helen"**).
It just makes these already low-effort distributions feel even more uninspired when the OT is so blandly descriptive; the only legal way to have a shiny Zygarde in Gen VII was to have one with the extremely crap OT "2018 Legends", as opposed to Xerneas/Yveltal's very-slightly-more-imaginative "XY&Z". I know it ties together a bunch of unrelated Pokemon released under the same banner but come on GF, be a bit more interesting about it. It's not that hard. Some Pokemon distributed to commemorate the 10th anniversary had the OT 10ANNIV (or "10 ANIV") which, while also not terribly inventive, I'm rather fond of because it's a slightly playful way of working with the shorter character limit in earlier gens and matches the ID number 00010 some of them had.
*There's actually a fun extra dimension to this I hadn't really considered until a while ago: because most of the catchable mythicals (Deoxys, Celebi, Mew, Shaymin, Darkrai et al) are so rarely distributed in shiny form, nine times out of ten a shiny one is self-caught. Adds an extra incentive to having the option to catch these species yourself, which is something I appreciate
**are the latter two names references to something? I haven't seen those movies