I can definitely see this happening, both Hyper Beam and Giga Impact. 200 BP moves that have great neutral coverage with a variety of other STABs is no joke, and nearly every pokemon gets them.
@ Normalium Z
- Nasty Plot
- Thunderbolt
- Hyper Beam
- HP Fire / Knock Off
Like, this set. What exactly can handle it?
+2 252 SpA Thundurus Hyper Beam (200 BP) vs. 252 HP / 4 SpD Latias: 336-396 (92.3 - 108.7%)
+2 252 SpA Thundurus Hyper Beam (200 BP) vs. 252 HP / 112 SpD Hippowdon: 480-565 (114.2 - 134.5%)
+2 252 SpA Thundurus Hyper Beam (200 BP) vs. 248 HP / 144 SpD Mega Venusaur: 320-377 (88.1 - 103.8%)
+2 252 SpA Thundurus Hyper Beam (200 BP) vs. 252 HP / 252+ SpD Assault Vest Tangrowth: 306-360 (75.7 - 89.1%)
This is one move that, just by virtue of raw power, can substitute for a bunch of coverage moves simultaneously.
Unaware Clefable and Quagsire are both 2HKO'd by a combination of one other move and Z-Hyper Beam. Chansey is powered through eventually. If it runs Knock Off it's checked by Ferrothorn and Excadrill, and if it runs HP Fire it's hard walled by Marowak-A... that's about it.
A bunch of other special attackers can use it pretty well, too. Serperior has shit coverage but Z-Hyper Beam patches that up a bit. Keldeo can lure a few things with it too.
Anyway, I'm really liking Ghostium-Z Aegislash. 160 BP Shadowballs ruin lives, it basically has no safe switch ins except for Mandibuzz (and Alolan Muk? He could be cool but I'm not seeing it ever.) You can do some riduclous stuff with Z-moves and I'm really interested in seeing what people come up with.