I'd like to see an Anno-type city-builder rebranded in terms of you being unspecified dark forces/eldritch being. So, like, you still have a population, but you need that population because their worship (or [enforced] sacrificial offerings) provide you with "power" (which could just be how you unlock more advanced structures and such). And you're still collecting resources and making production chains, but those resources are not things like iron and tools, but I don't know, body parts and wands. I suppose you could be a cult leader or mortal necromancer rather than an elder being. I haven't really fleshed (heh) out the idea yet but yeah, just Anno with a darker aesthetic.
Not going to happen, of course, because it's too niche of a concept. The Anno series itself isn't exactly a blockbuster in terms of popularity but they are still well-developed games, particularly in terms of the graphic and interface designs. Giving it a darker aesthetic (and thus, limiting its appeal) would only be done by an independent studio, and they very, very rarely have the proper or budget to do graphics or user interfaces well.
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I'd also like to see more games using the Final Fantasy Tactics aesthetic. I always felt it was a strong compromise between full detail animation and representative sprites. The sprites in FFT were very expressive, and lent themselves well for use in the cutscenes. I feel like if it were expanded to an open source platform, it could do well as a model/engine for a new generation of roguelikes. Imagine if something like Dungeons of Dredmor or tiled DCSS used it model: they could still have a relatively simple graphic budget, but the engine would allow for actual 3D environments, something missing in most roguelikes these days. And the ones that do have 3D environments tend to suffer precisely because they're still married to the 2D planar representation.
(PS: Screw War of the Lions for replacing the cutscenes with ludicrously bad animations and terrible voice acting.)