I'm with Denkt on this one. Also, unit upgrade costs seem absurd right now. To Upgrade from an Archer to Composite, and then to Crossbow in civ5 is about 180 gold on standard speed. To upgrade from an Archer to Crossbow in civ6 is 200 gold on
quick speed that we've seen. Horseman to knight was what, 100 gold on standard speed? Chariot to Knight was 190 gold on quick in civ6.
Furthermore, Units and Buildings require maintenance and these costs increase the more advance something is. For example, a Library may cost 1 gold per turn, but a university may cost 2. A warrior may cost 1 gold per turn, but a knight might cost 3.
Then there are the other uses for gold - The purchasing of tiles will be commonplace in this game - a regular part of the strategy utilized to develop and plan your cities since you'll want your districts in very specific spots and can't leave that up to the culture crawl. You can purchase buildings and units as usual and then you can spend gold towards great people which is probably the largest advantage you can acquire with gold. Oh, and of course there are the diplomatic uses.
I don't think gold is going to have any shortage of uses in this one.
(and the costs seem too high to utilize it for that purpose on any kind of regular basis).
High costs are exactly what promote a healthy need for gold as a resource as opposed to the opposite. If you're never generating up the amount needed to upgrade your units then all of your veterans would remain in the stone age.
But that's slightly off topic - Others have already mentioned the main problem is that sliders basically nullify the idea of strategic city planning. If I can spam commercial hubs and use them to invest in science - why wouldn't I? That narrows the path toward an optimal play style by finding the most worth-while yield (science usually), building your infrastructure primarily around that one, and then just use the slider to make up in the other areas as needed.