First of all, check Filthy's tier list on youtube, it is the most proficient list ever. After abusing this game a lot and winning sciences victories on deity before turn 200 on quick speed consistently peaking at turn 184 with America on an isolated, easily defendable position, and after trying a lot of strategies, my thoughts on the tier list are as follows:
The game is easier on faster speeds since the main way to catch up with the AI is to take away his production by killing his units and cities. The AI already has a huge advantage in science, so your window of opportunity is bigger on slower speed, he replaces units slower, upgrading comps to crossbows a bit later, etc. On quick speed, it's impossible to rush an AI with tradition because you don't have enough production to build units fast enough and not cripple yourself afterwards. If you are lucky, you might do it with liberty, and having early game unique units helps a lot, and I'm not reffering to the Maori warrior, I'm reffering to Byzantium, Greece, Babylon, Rome etc. I can't understand why you underestimate Dromons. Yes they are situational, but if you have an opponent with a capital on the coast you can actually rush it with 5 dromons, which is very cheap. That's huge. You get double the land, you eliminate a neighbour. Also, if your capital is attacked you can defend with dromons, they stack with archer units. You can concentrate on something else, like getting a religion, and let the dromons defend your cap. This is not a situational bonus. I suggest you look at other people's ideas before starting to make tier list and stuff. This game might not seem so, but it's very complex and there are a lot of hidden things to learn about it still. My tier list is as follows, I will explain why for each civ. The settings are quick speed, pangaea, 6 players. Quick speed with 8 players is unbalanced, you can't kill enough AI's fast enough, the map is bigger, takes too much turns to get to them before they get to the next era units. Standard map is supposed to go with standard speed. Quick speed with small map. etc. No DIplomatic victory allowed, that will affect Venice's ranking. So here it goes:
Tier 1: Babylon, Korea, Poland, Maya, Inca, China, Persia, Arabia, Egypt
Tier 2: Venice, Huns, England, Austria,Shoshone, Ethiopia, Spain, Greece
Tier 3: India, Russia, Songhai, Siam, Germany, Rome, Aztecs, Siam, Zulu, Brazil, Mongolia( Keshiks obsolete too fast), Assyria, Byzantium
Tier 4: Denmark, Indonesia, Ottomans, America, Morroco, Portugal, France, Carthage, Sweden ( downside of having too many friends is that the AI will also be friends, hence no war between them)
Tier 5: Netherlands, Polynesia, Japan