BIG post incoming, sorry in advance! TL,DR at the bottom
I know it's been discussed on this thread previously, but I also think GW could be "struggling" with what to do with our army. I mean, they have taken our primary army abilities (summoning & teleportation) and given them to virtually every other army in some capacity. When you come back to the original army, how do you make that army feel fresh?
Yeah, that's probably what they're thinking as well. When releasing new battletomes, they seem to prefer big re-works over minor buffs and balance changes. In fact, they're really not concerned with balance at all, since each new faction that comes out contributes more and more to the power-creep. I have a feeling they'd rather re-work Seraphon than just buff them to be able to stand up to the other factions. But coming up with an entire new gimmick for an existing faction is probably hard when you've been releasing so many new factions, each with new gimmicks of their own.
They could add back stuff that was removed from the old world, or they could add more stuff to us like celestial meteors, or seraphon units causing penalties to hit as they are blinded or burned by us. More space stuff would be cool
This could be a big part of why they don't know what to do with us. Do they stick with the Aztec/Mayan theme of seemingly primitive warriors who secretly have insanely powerful magic and tech granted to them by gods who were around even before the world began? Or do they "modernize" the Seraphon and give them more spacey abilities. Could definitely see them agonizing over that, especially since Stormcast were essentially "let's try and get a space marine-esque faction into fantasy because 40k is more popular."
I think they made some bad choices in that regard, not every army needs a teleport. They should have kept it for a few select factions.
Couldn't agree more. They're cool mechanics, to be sure. But not every army needs them, nor does it even make sense for every army to have them. But we all know that GW seems to do things more based on the Rule of Cool than on what actually makes sense. Thus the continued power-creep...
I would rather them stick with the old Aztec theme and focus more on improving our magic and unit strength. Keep what we have (summoning, teleporting), but make the Slann better wizards with a way to get their own bonus to casting. Un-nerf Lord Kroak! Lore-wise he should be even more powerful than Nagash, but with Nagash being one of the two main characters in the lore as of now I can't see them doing that, unless they actually wanted to make Seraphon more relevant to the main story. Currently the main story of AoS is basically Sigmar vs. Nagash with Chaos being a pain in the butt every once in a while. All the other factions are just trying to survive or fighting because that's what they do. The Seraphon are the only faction to actually survive from the old world (faction, not individual characters.) and their goal is to stop Chaos, which should still be the main villains of the setting. Seraphon deciding to get down to business and actively go head-to-head with Chaos and the Skaven once again would make for a really interesting story.
As for our units, Saurus are supposed to be incredibly strong warriors. The regular warriors should get better saves and rend, while the guard should get two wounds and better saves to make them the defensive units they're supposed to be. Skinks are fine as they are, they serve their purpose well. We just need to have options other than skink spam, lol! Knights need better movement and either a buff to defense or offense. Make them into tanky cavalry that can charge into combat and then hold the line, or make them deal more damage so that when they attack it actually feels like a cavalry charge. I would personally prefer the offensive option. They are lizardmen riding velociraptors, after all

Carnosaurs should be some of our most killy units, but also be able to survive more than one round in combat with another monster or units of troops. If they wanted, they could lean more into the "monster hunter" role for them and make them really good at taking out other monsters/mounted characters, our answer to stonehorns, big daemons, mammoths, dragons, etc. Razordons and Salamanders are in good shape, imo. So are rippers and terradons. Kroxigors definitely need some attention, though. They really ought to take a page out of Total War's book in this regard, just make them high-rend elites that can mulch hordes but also hold their own against other elite units. Troglodon just needs some minor buffing. It already does some pretty cool stuff, just needs a small boost in power. Bastiladons are in great shape, but stegadons should be our linebreakers. Somewhere in between the murder machines that the carnosaurs should be and the living tanks bastiladons are.
For how to make our army fresh, I personally would like to see them lean heavily into the fact that we are LIZARDmen. Reptillian warriors who should feel no pain and fear no enemy. Lots of armies have army-wide bonuses. We should get something like a scaly skin or feel no pain save after save that helps us better withstand the insane amount of mortal wound output that new armies seem to keep getting. I'm mostly thinking of how the Lizardmen play in TW:W2 here. We're a very resilient army with all the saurus units being very good at outlasting the enemy, skinks being there for missile fire and support, and dinos and kroxigors being there for the punch when you need it. That's how I would like to see the Seraphon play, tbh. Along with the Slann being able to cast more and better magic and not having to sit in the back doing nothing but summon more skinks to dance around objectives with.
I still think we should have summoning and teleporting, but would prefer to see it become less of the main focus of our army. Right now, the idea seems to be "It doesn't matter if the Seraphon units suck, because they can just summon more and zap them across the battlefield wherever they want." The lore and types of units we have say that we should be a resilient, powerful army with the extra strength of having strong magic and mobility. They way our army is currently set up is all of our units are seen as disposable chaff because who cares if they all die they can just get summoned right back, right? But the fact is we can't summon enough to make up for the devastating losses from trying to actually fight pretty much any other army, and the fact that summoned/teleported units aren't always useful until the next turn is a major weakness.
I think it would be more interesting if we kept teleporting as it is now, but changed summoning to make it so that we accumulate points in ways other than sacrificing spells. Doesn't Tzeentch get summoning points from SUCCESSFULLY casting spells now? I could be wrong on that. But I'd personally rather see something like that than our current mechanic of sitting around doing nothing for a turn or two, only to summon something that most likely won't be able to do much more than try to tie up an objective before it dies. I guess it comes down to the fact that our summoning is a defensive, reactive mechanic right now. We wait, and wait, and then try to summon something that might be useful, but have to sacrifice a lot to do so. I'd rather see summoning be a snowballing effect. Where the points build off our successes and when something is summoned it's like a finishing move in a fighting combo rather than a panic button to try and stem the enemy tide.
TL,DR:
I think GW likes our faction as much as any other currently existing faction. New ones will always get more love and attention because they've gotta hype the new stuff for sales. I just think they aren't sure what to do with Seraphon given that their lore is disjointed, their warscrolls are out of date, and what was once unique about them has become common to a lot of factions. They prefer re-works to mere updates, but probably don't know how to make a re-work do them justice while not totally changing the lore, playstyle and aesthetic of the faction. Personally, I hope they go for a "mere" update and leave our Aztec lizards riding dinosaurs theme intact, while remembering that the Slann are supposed to be the best mages out there!
Also,
@Lizerd and
@Erta Wanderer, do you think I would have a hard time getting people at my gaming store to let me play with those rules? I'm trying to get friends to play AoS with me, but the chances are few and far between. I think that if I tried to take those fan-made rules to the game shop, it would probably be looked down upon...