Firaxis has the exact opposite experience: beyond Earth had extremely similar gameplay to civ5, without the historical factions, and it went poorly. Historical factions are free worldbuilding, just like the nintendo characters in super smash bros don't need exposition because players presumably already know who they are.
The difference is, Firaxis makes a decent core game but isn't good at building a fantasy world. Beyond Earth did badly because it wasn't immersive rather than because it was a bad game. Amplitude is the exact opposite: they're notable for their flavourful factions and good writing - but the underlying games are ultimately mediocre.
If you're taking a real-world setting that piggybacks on existing flavour, you want a company with a history like Firaxis' more than one like Amplitude's.
Now, the HK gameplay system does, for many civfanatics, seem to be offering a promising alternative - the economy/districts/settling/tiles/etc could be seen as an evolution of what civ6 did.
From what I've seen it's basically culled from Endless Legend, which is a less sophisticated version of what Civ VI did (for all that it probably inspired Civ VI). It has visual appeal (which frankly is also much of the appeal of Civ VI's system - the districts being in the landscape don't really add much compared with the bonuses from having certain terrain in the city radius that older Civ games used, but even recognising that going back to Civ V feels lacking to me just because its cities aren't unpacked), but it's a replacement for citizens rather than Civ VI-style districts. Basically Endless Legend automatically works any tile you've developed, so it's much like having a specialist in Civ IV or earlier - a static resource gathering mechanism.
It's admittedly less useful than I'd like it to be - and than it was traditionally - to manually move workers and specialists around in Civ VI, to the point that it's approaching busywork that could be automated rather than a meaningful strategic choice, but being able to move citizens or otherwise adjust your tile yields is a core part of Civ. I can see that newer players to the franchise might see less of a point to it now that the automated placement is optimal in most situations and so might like a system that automates the process, but the Endless system isn't doing anything Civ doesn't already.
IMO it will really come down to how players narrate their games - in civ you are one civ for the whole game, in HK you add new cultures to your empire each era. So really you are playing an empire in a generic sense more than a civilization. But many of the things they are doing wouldn't shock me as new mechanics in civ7 - like the outpost and territory system, or the slightly more flexible district system they have.
It's striking how much of the flavour in Civ I find comes down to simply having so many of the familiar city names around. NFP Civ VI feels more 'complete' to me when Constantinople and Thessalonica are in the mix along with all the pre-existing stalwarts - while at the same time I get a healthy mix of city states I'm not familiar with and those I wasn't expecting to see in a Civ game but welcome (such as Ayutthaya in the current version, and Antananarivo since Civ V). I found Civ VI uniquely flavourless for a Civ game right up until they hit on the idea of culturally-defined names for landscape features.
I think a lot of people will feel the same but not necessarily consciously - Civ's flavour comes from the world more than from the identity of the civs. Having a civ that starts out as Phoenician and can turn English at will, aside from being thoroughly counter-immersive to me, is not I think what people want from civs that evolve over time and I think Amplitude has misread the part of the audience that wanted civs that evolve. It would be very complex to implement, but I think what people who wanted to break from Civ's one-civ-all-the-time structure wanted was something that could develop procedurally, such as developing improved sailing and fishing skills by settling a coast, in a way that settling a coast and actively deciding "Okay, now I'll be Phoenician for a while" doesn't capture.
Basically, Humankind hit on a halfway house that I suspect fewer people than they want will consider satisfactory. Babylon aside I'm not a fan of Civ VI's eureka/inspiration system, but I think it's on the right track in understanding the sorts of mechanic people were asking for in a way Humankind's is not.