I think probably there's some confused ideas going on here.
the whole 'tall vs wide' doesn't need to exist in a civ game. Yes, CivV added in mechanics and limiters that made 'tall' a thing (4 city tradition style) but that was a strategy developed by players who didn't think it was worth it to fight against the mechanics to expand more; and then it got reinforced more by the developers over the expansions. It made things look very ugly (missing lots of space coverage) and wasn't organic (4 and done, then fall asleep for the win).
ICS (in previous games) was also bad. it's pretty obvious why. ICS relied heavily on widely spread pop gains along with (heavy focus on) the city tile yields. Effectively, more hex yields and more 'easy' city center yields outperformed buildings/etc inside a well developed/grown city.
Both forms of empire relied on shoving one specific concept to the limit.
I expect that neither should in fact exist in a game of civ.
What it's looking like in CivVI is that districts make the world go round - but not exclusively. If we take it that districts are the main drivers of their specific yields (and for specialists/great people/adjacency bonuses that seems to be the case from what we've seen so far), then in fact growing an individual city taller means more districts, which is 'better' in one form. But you still need expansion to go find those district locations that will give you greater benefits (though we haven't seen anything yet that really drives home adjacency bonuses of say +5 being orders of magnitude better than +1 or +2).
Also, I think it's fair to say that 'wide' inasmuch as 'lots of cities, low individual investment' -- Ie focus on 'lots of spread out population' for hex yields and basic yields from pop (civV science for example) is also not a boon in the system. Yes you can get more 'strategics/luxuries/etc' from covering more lands, but those cities won't be getting you that better yield. It also is a risk for getting run over by a better military. An easy prevention of the 'spam' plan is to make cities not be able to buy up all the good units without some development first. If you can't buy more units in the far off expansions, you can't protect them as well.
Which leaves it back in the hands of the 'wide but tall' play -- the middle ground. You do want to expand, but you do also want to get taller and have more infrastructure per city.
Speaking of that though, I don't think that 'wide and tall' is the answer here either. Not every city is going to get tall in CivVI. I say that due to the housing restrictions (water needs. there won't be rivers everywhere), partially from what we've seen from amenities so far as well as the district adjacency bonuses. Not everywhere is a 'good' location for a district so that investment will need to be able to pay off in a timely fashion.
So it's entirely possible that you could end up with an empire with some strategically located 'tall' cities which can grow and add in their specialized districts (or just lots of them) and have the lands to mass farm/etc for growth. Then you would add in the periphery cities. These cities wouldn't be growing 'tall' but would get enough pop to support a few districts. So you'd end up with a blend of tall and small cities based upon what you need and the space available.
Ie, Capital start is not on the coast, but there's a small area of land on the coast that you could use for a port. Drop a city in there and now you can get a harbour in and maybe another district. It doesn't need to be a huge city, but one that is just big enough to produce naval units and possibly add in trade. the 2nd district could be an encampment (to protect the harbour vs bad neighbours), a commerce district (to help with using the city as a trade hub) or whatever else happens to be needed or wanted there.
Could be that the a city location can get a really nice adjacency bonus for a campus and a holy site, but not be able to support the food required to grow more due to limited space. It would still be worth expanding to go get that space, especially if you're lacking the requisite nice terrain around your 'core' cities.
So I think the answer isn't 'there should be these wide and tall options because that makes it a choice', but rather that the 'choices' you make (and terrain features) define how many cities you have or how tall the cities in your particular empire get. Shift the ideal away from 'two' generic empire styles towards more choices per city.