At some point, when an MMO gets to 8 or 10 years, encounters start becoming stale. This is understandable but the degree to which staleness permeates the newest normal raid series is just too much. It's weird that the dungeons for Endwalker feel so fresh compared to ShB ones, but this tier of raids is just completely uninspiring, and I highly, highly doubt that Savage will change that outlook. We have seen these mechanics over and over again and I feel like SE has just completely run out of ideas for new mechanics or new approaches to raid design. The creativity that I saw in HW is just not here anymore.
Square Enix needs to be more daring in its encounter design and try to be less concerned with difficulty balance and cohesion, which IMO are factors that limit their creativity. The current philosophy of using basic mechanics (left/right half-room cleaves, stack, spread, proximity, GA-100/Flare, etc.) as building blocks for raids, while efficient and often creating elegant raids, get very very stale for any veteran. We have seen the same frameworks too many times now (e.g.: debuff soup mechanics (Neo Exdeath, Final Omega, Oracle of Darkness)) as well.
Variety is the spice of life, and so too it goes for raid design. While having a majority of mechanics be stuff we've seen before is fine, or having mechanics be slight variations on existing mechanics (such as spreading by tile instead of player position as in Titan), this new tier truly has nothing creative to show for it. And again, I really, really doubt Savage will be much different (and even if Savage is much different, why did they not even attempt to incorporate the distinct elements in Normal which far more players go through?). I really hope Square Enix tries harder on creating variety for raids.
Now that Savage is out...
I've cleared the tier and it just doesn't seem like there was a lot of creativity this tier. I'm sure the developers can choose to make a raid tier memorable if they tried, but I'm guessing they're holding back because of some preconceived notion of Savage being a safe, accessible main piece of content that's the main attraction for a lot of players, resulting in them not daring to take risks. It's a shame.
Too many mechanics this tier just feel samey. I think Fountain of Fire and the role-based mechanics in P4S feel interesting enough (reminds me of O3). But it's too bad they never really expanded on it.
A huge part of why the Savage raids feel lame is because the flow of the encounter is such that you're mostly just solving puzzles one by one throughout the encounter. It feels disjointed and also means that any spark of creativity only gets seen for half a minute or so. Alexander raids had a good flow - mechanics stacked on top of each other and they were not discrete. Mechanics were often combined on top of each other which gives it a hectic and tense flow.