So I've been steadily climbing back into competitive Pokemon after a pretty long break from it, and have been stepping back into this gen's RU. So far I've been having fun, I won't common on what deserves to be banned, but just a few thoughts so far from what I've used and such.
Lucario is phenomenal. Its standard SD set is a very powerful late-game cleaner, with +2 priority with Extreme Speed, especially with a Swords Dance boost in tow, being really good for cleaning in the late-game. Even aside from that, Close Combat and Iron Tail hit really hard against slower mons, and you can also give up Iron Tail for something like Ice Punch depending on what your team can cover for it. The special set is also pretty strong for dealing with checks to the physical one, being able to hit Doublade and Necrozma hard with Dark Pulse, and such (Vacuum Wave is decent for NP but not all that powerful).
Crawdaunt is also a very threatening Pokemon, since Crabhammer and Knock Off hit extremely hard provided Crawdaunt gets an easy switch-in, which makes it a massive threat to balance / bulky offense teams since there are very few threats that can safely switch in on it, Chesnaught being one of those few, and everything else is either easy to wear down or succumbs to two hits or so. Aqua Jet is also quite strong and helps Crawdaunt get the edge over some offensive threats on offense, so it's not completely helpless against offense either. It doesn't completely wreck teams all the time but when it gets in it's easy to get at least one kill which can easily work to a team's advantage and screw up the opponent as a result.
Dragon-types have become quite common this gen, and there are many I've had fun with. Kommo-o is a really cool Pokemon on offense, since Dragon Dance sets are wonderful due to Kommo-o's nice bulk and good power, which help it set up and sweep with Outrage and such, having good coverage with Poison Jab and to an extent something like Earthquake or...Sky Uppercut (lol this is seriously its best Fighting STAB). Specs is also fun since Clanging Scales hits pretty decently hard from Kommo-o, and it has good coverage to back it up here and there (Focus Blast is also pretty strong). Underneath all that it has good bulk, a nice typing, and the abilities are also great, since Bulletproof and Soundproof both have uses in helping Kommo-o block certain moves from certain threats. I also have been having a lot of fun using Goodra, which is a very solid mon on bulky offense due to its high special bulk making it a wonderful check to many threats such as Venomoth, Shaymin, Roserade, and a number of common special threats as well as sun and rain teams. Sap Sipper is an awesome ability which helps Goodra block Sleep Powder and Seed Flare, among those other moves, and Specs hits super hard with Draco Meteor along with fantastic coverage in Fire Blast, Sludge Bomb, and something like Muddy Water. I think Band might be able to work with Goodra's good physical movepool but I've yet to test that. Kyurem is definitely a prominent threat this generation since SubRoost and Specs are both strong as hell, the former also being a massive pain in the ass due to Pressure and a lot of bulk. Ice Beam is also really good as STAB and has great neutral coverage, and also gives it the edge over the common Gligar and Donphan, as well as other Dragons.
Weather teams have also been pretty fun to work with since despite the lack of Drizzle, Rain teams are still very strong with Kingdra and Tornadus both in the tier, combined with other common abusers such as Kabutops and Ludicolo existing and the old Liepard and Uxie still existing, and in general are very tough to deal with since rain-boosted Waterfalls and Hydro Pumps/Surfs from Kabutops and Kingdra hit hard beyond all belief and they outspeed almost everything under rain. Tornadus is also crazy strong. Sun teams have been workable with Torkoal in the tier and the use of things such as Venusaur and the like being good, though rain is definitely the more powerful playstyle since Kabutops and Kingdra have the means to work well on their own. Sand I think is also pretty usable with Gigalith being in the tier and Stoutland being a strong sand sweeper, though I've yet to see many sand teams in what time I did spend so far.
Other than that, some old threats are still doing wonderfully as they have before. Bronzong is pretty awesome with its ability to somewhat check Shaymin and Nidoqueen and the like. Mega Glalie has also been pretty killer as a breaker especially with Grass, Ground, and Dragon-types being common in the tier making its powerful Ice moves extremely good to use, it's a really wonderful Pokemon right now as it was before. The lack of Alomomola in the tier definitely helps it too (it's been years since RU hasn't had Mola as a major force, man it's nice and refreshing for once). Sharpedo is also really awesome as a cleaner, and Psychic Fangs is also a nice boon to its movepool to give it the edge over certain threats such as Kommo-o.
So far the meta has been pretty interesting, hoping for Lucario and Crawdaunt to be banned/suspected soon like everyone else, but other than that it's been pretty fun trying out the beta RU metagame. It has a lot of similarities with last gen's UU for that matter too with a lot of 6th Gen UU staples in the tier. This is just my massive dump of thoughts so far but it's been very interesting playing the early RU meta, I may have more to say the more I play.