I'm thinking that the unit cap for tall play might need to be increased somewhat. I'm consistently finding that Tall/Tradition/Peaceful play has become overly difficult to pull off relative to before. I'm not sure when "before" was but I do remember being able to largely avoid DoWs from non-warmonger AI when playing tall in the past, usually by playing the diplomacy game somewhat intelligently (making friends via trade/denouncements/bribes etc). These days it seems like a low unit cap trumps any attempts at diplomacy. In case it's relevant I play Deity/standard/standard/continents++ with VP+EUI only.
How it seems to currently go:
From very early on in Tradition playthroughs I basically sit at my max unit cap at all times and still often have a very low army score in the demographics screen. This is with me trying to prioritize unit cap buildings somewhat (secondary cities are often building barracks/walls before things like market/library just for unit cap) and often settling wider than I otherwise would to try to increase my cap. I'm not attempting to go on the offensive in these games, I'm just trying to have an army size that doesn't make the AI decide I'm easy pickings and constantly DoW. I'm totally OK with not being able to deter warmonger civs but these games tend to include DoWs from basically everyone for a majority of the game (even more passive civs) and as far as I can tell the issue is my unit cap. Note that even a meager unit cap is usually enough to allow the player to avoid losing cities/units while on defense, assuming you settled cities defensively and use your units well. The problem is that the constant DoWs from everyone make diplomacy, trade, etc a non starter and generally make the game less fun.
The only path I see for tall/peaceful games to have a decent enough army to deter constant DoWs would be to highly prioritize armory/academy and castle/arsenal techs as well as unit cap giving wonders (probably starting with great wall and himeji). Reaching for those techs/wonders is sort of counterintuitive for a tall/peaceful game that likely wants to reach for the top of the tech tree most likely but that seems to be the only answer in my experience. I guess I'm questioning if that's what we want the game to encourage. In my mind it would be something more like:
You can play Tall/peaceful and avoid constant DoWs due to being perceived as weak as long as you do not let your military lag. This means keeping your unit count close to the cap and giving military techs/buildings reasonable priority. If you sit at, say, <80% of your unit cap, reach too far along the top of the tech tree, neglect to build wall/barracks line buildings, or fail to upgrade/modernize your army then you should be punished with aggression, though- don't be greedy! A higher unit cap for tall play would require more production/gold to go toward the tall player's military but would hopefully keep the player from being perceived as weak.
Defensive military wonders like Great Wall or Himeji probably shouldn't be required in order to avoid perceived weakness from everyone. They should be the wonders you go for if your neighbor is a threatening warmonger and you know that normal deterrence isn't going to cut it so you want some insurance against his inevitable DoW.
I haven't seen these issues as much in wide/Progress play. More cities means more unit cap and it seems to be enough to avoid the weakling label. I certainly don't have these issues in Authority/warmonger games, either- those playthroughs have tons of tools to increase your perceived strength and if anything, DoWs are welcome in that they allow me to conquer without triggering DPs
I'm wondering if others see these issues in their Tall playthroughs as well. As for how to address it: I'm thinking Tradition could probably use some sort of larger unit cap from population in the capital mechanic? Or perhaps the player should have the same unit cap bonuses as the AI currently has? Having a higher unit cap allows you to build more military but it also requires a lot of production, GPT, and lump sum gold for upgrades so there are drawbacks even if it allows you to field a larger army.
How it seems to currently go:
From very early on in Tradition playthroughs I basically sit at my max unit cap at all times and still often have a very low army score in the demographics screen. This is with me trying to prioritize unit cap buildings somewhat (secondary cities are often building barracks/walls before things like market/library just for unit cap) and often settling wider than I otherwise would to try to increase my cap. I'm not attempting to go on the offensive in these games, I'm just trying to have an army size that doesn't make the AI decide I'm easy pickings and constantly DoW. I'm totally OK with not being able to deter warmonger civs but these games tend to include DoWs from basically everyone for a majority of the game (even more passive civs) and as far as I can tell the issue is my unit cap. Note that even a meager unit cap is usually enough to allow the player to avoid losing cities/units while on defense, assuming you settled cities defensively and use your units well. The problem is that the constant DoWs from everyone make diplomacy, trade, etc a non starter and generally make the game less fun.
The only path I see for tall/peaceful games to have a decent enough army to deter constant DoWs would be to highly prioritize armory/academy and castle/arsenal techs as well as unit cap giving wonders (probably starting with great wall and himeji). Reaching for those techs/wonders is sort of counterintuitive for a tall/peaceful game that likely wants to reach for the top of the tech tree most likely but that seems to be the only answer in my experience. I guess I'm questioning if that's what we want the game to encourage. In my mind it would be something more like:
You can play Tall/peaceful and avoid constant DoWs due to being perceived as weak as long as you do not let your military lag. This means keeping your unit count close to the cap and giving military techs/buildings reasonable priority. If you sit at, say, <80% of your unit cap, reach too far along the top of the tech tree, neglect to build wall/barracks line buildings, or fail to upgrade/modernize your army then you should be punished with aggression, though- don't be greedy! A higher unit cap for tall play would require more production/gold to go toward the tall player's military but would hopefully keep the player from being perceived as weak.
Defensive military wonders like Great Wall or Himeji probably shouldn't be required in order to avoid perceived weakness from everyone. They should be the wonders you go for if your neighbor is a threatening warmonger and you know that normal deterrence isn't going to cut it so you want some insurance against his inevitable DoW.
I haven't seen these issues as much in wide/Progress play. More cities means more unit cap and it seems to be enough to avoid the weakling label. I certainly don't have these issues in Authority/warmonger games, either- those playthroughs have tons of tools to increase your perceived strength and if anything, DoWs are welcome in that they allow me to conquer without triggering DPs

I'm wondering if others see these issues in their Tall playthroughs as well. As for how to address it: I'm thinking Tradition could probably use some sort of larger unit cap from population in the capital mechanic? Or perhaps the player should have the same unit cap bonuses as the AI currently has? Having a higher unit cap allows you to build more military but it also requires a lot of production, GPT, and lump sum gold for upgrades so there are drawbacks even if it allows you to field a larger army.