By "essential" I mean "5/5, personally I would love to see them".
Germanic civ (esp. Goths) - essential, Germanic era II and era III civs really need non-Roman, non-Greek progenitor, plus Goths would be super cool. They'd also double as a progenitor for later era Spanish, Portuguese and Italian civs (kingdoms of Visigoths and Ostrogoths).
Gauls - essential, you add them and you have a progenitor civ for like half of European continent.
Yamato Japan - not essential though I'd like it. Mainly because ancient Japan was really underdeveloped (writing only began in the early 6th century, for example, half a millenium after Koreans) and I'd be fine with beginning with Han or ancient Korea before becoming Japan.
Steppe civ (esp. Scythians) - essentials, enormous potential as a cool progenitor civ. Scythians in particular would be crazy, as they could be a sensible progenitor for Mongols, all Turkic peoples, Iranian civs, some Indian civs, Central Asia in general, Ukraine, Hungarians, Bulgarians, and even Poland if you stretch it (and are aware of the Scythian origin myth of Polish nobility

)
Varangians - why are they even in a poll? I have never seen them requested by anybody.
Fatimids - I would reframe them as "Islamic Egyptian dynasty" or Fatimids/Ayyubids/Mamluks and they I'd even consider moving them up to "essential" vote, since I love the idea of civ game finally acknowledging the existence of post-ancient Egypt. It could even have its own full lineup, with Muhammad Ali's or Nasser's Egypt in the third era.
Oman - at first I wanted to vote for them as poor inclusion due to their limited importance, but then I realized they are almost unique (after perhaps Tunisia) as a navy-oriented Arabic civ, so they are fine.
Edo Japan - I'd reframe it as "exploration era Japan" since it doesn't need to be Edo. Anyway I'd consider it essential in a way, because Japanese civ beginning only in the modern era feels really off.
HRE - separate from Austria. Essential imo- we have Charlemagne, finally we have a civ game where they make sense to be added, they'd be a progenitor to many civs, and they are much cooler than Teutons as a progenitor for Germany imo, due to being less... stereotypically militaristic and expansive.
Ottomans - see, now this is the "essential civ" which I'd also call "should be in the base game"!
Modern indigenous civ - essential, I want to start as NA indians and end as NA indians, not USA.
Italy - essential, they really deserve to be in the game, preceded by some era II Italian city state...
Safavids - they could be named "Iran" and combine stuff of Safavids, Nader Shah, Zand dynasty, Qajar and later Iran.
Anyway I'd consider them essential, because I desperately desire non-Achaemenid Iranian content.
Ethiopia - essential, the most notable modern era African civ, and we already got Axum.
Sahel civ - we practically only have Sokoto as a decent modern choice here. As unpopular as this notion is, I'd call it essential,
because I'd like for every part of Africa to have its own lineup, not being all mashed together. E.g. Ghana -> Songhai -> Sokoto.
I would also love for Nigeria to have some more representation.
Zulu - poor inclusion. Why? Because they've been in every civ game ever, and they always have the same boring features and design.
Canada/Australia - poor inclusion, because we had way to many Anglo-attached civs last time...