Is any of the Stellaris DLC worth grabbing on the Steam sale?
In a general way there are 3 types of DLC for stellaris: Cosmetic; small DLC (story packs) and big DLC (expansions).
Let's start with cosmetic:
- generally speaking cosmetic add variety to the galaxy (new portraits, new ship and stations models) which means it makes the random generated galaxies much more unique.
- Humanoids Species Pack is not worth buying IMO because the portraits are very "human". I know the pack is based on humanoids species but i don't think there is a single "alien feeling" portrait; they feel mostly like star trek humanoid species; that said the ship models are superb and cool to use. The new voices for vir are also quite unique. IMO this pack is only for people like me that have played 100s of hours and want more variety.
- Plantoids Species Pack is a small recommendation for me. While this pack is expensive for its content, the new portraits are amazing. Seeing the plants come to life in game make the galaxy a much stranger place and thus more satisfying to explore.
Small DLC:
- generally speaking for me these are the best "deals" they add a lot of content to a section in the game and thus make the game feel more satisfying.
- Leviathans Story Pack is a recommended buy. It adds 3 mechanics that i enjoy: mid games bosses, these leviathans are a lot of fun to defeat the first time; enclaves, trading and commission art pieces add to the immersion of the game; "war in heaven", a fight between 2 fallen empires that usually ends in a galaxy "world war". For me this expansion adds a bit to mid game and makes it less boring if you are stuck between bigger/powerful empires.
- Synthetic Dawn Story Pack I recommend this pack IF you want to dabble with machine empires. These empire while fun mostly re-use the mechanics from the base game so you are not losing much. The coolest thing is a new fallen empire which has its own storyline. There are very few robot portrait but those that exist are very cool.
- Distant Stars Story Pack is a recomendation from me IF you already know most anomalies. This DLC adds a lot to the early game specially on the anomaly front. It also adds 3 new leviathans. Worth buying if you want to spice the early exploration phase.
Big DLC:
- these revamp a lot of mechanics to a lot of ethics so you won't notice their full effect on 1 campaign so they feel that they have much less content then the smaller DLC. For example spiritualists have unique ascension perks in utopia, with unique storylines and events. If you don't play as spiritualist and take that ascension perk you will never see that feature.
-Apocalypse I recomend this DLC IF you want more features for war. The 2 new features that i really enjoyed are the "death star" like superweapons and the titan (works like a flagship). It has a few non war features but those felt very inconsequential to me. If you want to build a death star this is the expansion to get.
-Utopia I don't recomend this DLC unless you have played a lot of hours. Some features of this DLC have been addded to the base game so it has lost features. In a nutshell it revamps late game by allowing these super buildings like halo rings and dyson spheres. These structures are very late game, I usually build them while the end game crisis is ongoing however if you enjoy building tall this expansion makes that very viable since you can build habitats which work like very small planets in the mid game. One cool thing about this expansion is the ascension perks which are like buffs with mini storylines, for example you can turn your species psychic and then have special events and can even "spy" on fallen empires getting their technology.
That is my opinion on the DLC of stellaris. DO note that i really enjoy stellaris so i'm highly biased to the gane and has such i probably have a lot more tolerance to problems then most people.
IMO you should look at the features and see how much you value them and just wait for the DLC to reach the right price for you.