Critique of above Constellar deck:
Hawwa has little purpose beyond trying to fetch maybe a Sombre. Pollux doesn't get its effect off, trying to get Kaust is a waste of time (not strictly r5 build, and thus doesn't reliably get out another level 5), and it's not like you get an activation off of Sheratan anyways. Plus, you don't get to do instant beats with the monster you summon, which removes quite a bit of the damage push potential (make Omega, attack with everything because you don't care about S/T).
Leonis is kind of weak if you're not running the level 3 Gredi. The single-use case of summoning Sheratan and making Hyades is really not that great.
On the case of Hyades ... it's not that good either but at least you can make instant Ptolemys (regardless of whether you get the effect), which is alright.
Ptolemys should probably go to 2-of. It's a very good card.
I would actually say Tiras is weaker than Zenmaioh, because Tiras can't blow stuff up instantly and may be a liability in the face of combat stoppers (i.e. D.Prison or Marshmallon / Reaper, because then you can't push for as much damage or even risk losing your guy).
Papilloperative is pretty weak. Either run Maestroke or another copy of Omega. In fact you could probably either cut Zenmaines or Leviair for Omega (I'd recommend Zenmaines, you rarely make level 3 with the suggested changes anyways), because 2nd Omega is just as important as 2nd Pleiades.
Although Star Cradle sounds good (and is not that bad), you often do not need the extra power afforded by it and you are unable to push for damage on the turn you play it... a lot of Constellar is trying to push for damage / tempo with Pleiades and Omega. Think on it! You could play a Pot of Avarice here instead.
Traps are probably fine ... though there is nothing you need to Safe Zone, so maybe try Xyz Reborn as a 1-of (Reborn -> Pleiades, bounce something at SS2, overlay for Ptolemys in your next main phase). Also I would run 2 Torrential over the Mirror Force / Dimensional Prison lineup ... since you can just Omega in resp to Torrential and make your opponent lose their field.
Re: Photon Slasher or Photon Thrasher (one is level 5, the other level 4 - I assume you're talking about 2 cards here) - they're worse than Cyber Dragon and Ghost Ship. Yeah, don't bother. At least you can do cool stuff with Cydra and Ghost Ship (like beating stuff in the face) - you can't with Thrasher and Slasher. They're pretty weak unless you're a deck that actually cares about protecting a single beater (and the Warrior typing of Thrasher) - for example, HERO beat back in the day. I run a single copy of Thrasher in Blackwings, as replacement for the third TK Raioh that was lost from the banlist a while ago, so there you go.
ON A COMPLETELY DIFFERENT TOPIC:
Very interesting reveals from Shadow Specters' full set spoiler. Labradorite Dragon is a new level 6 Normal (!!) Dragon-Type Tuner. This is actually important, because with some clever manipulation we can in fact make Starform Dragon in Hieratics, which is at least something to think about. Plus there's nothing to be actually lost by playing it, since aside from the loss of a Tempest target (Luster Dragon #2) there's no reason not to play this guy. (The necessary level 5 could be either Eset / Nebthet or Curse of Dragon / Parrot Dragon, the latter is a Tempest target without any loss of offensive stats - not that we care about those but still.) Chauchow-chan is another hand trap (but probably not that useful ... unless maybe you are Bujin? but even so). Genomics Fighter is interesting, I guess, because you can make a bunch of Type-specific Synchro monsters with it (I'll look up some good use cases for it later). Risebell the Star Awakener (second incarnation of Risebell?) is pretty alright - instantaneous rank 5! Plus, mess up your opponent's Xyz Summon (or Synchro Summon I guess). Breath of the Divine Serpent is hilarious, but I can't think of any immediate usage for it (except once again, in Hieratics ... damn); it is a very utilitarian card, however, and I foresee great things coming from it.
(Other good cards are Drewes the Unseen Druid, Pot of Duplicity, Pomp and Circumstance, Mistake, and Grisaille Gaol, among others... but those have been previously spoiled, and this post focuses on previously unspoiled stuff, so.)