As a caveat to this post, keep in mind that I'm playing Germany on the YNAEMP 22 civ map, King Difficulty, Normal Speed, meaning that balance may be different than in different situations.
As one would expect, I am first in food production due to the immense growth bonuses that Tradition gives across the board. I am second on population due to India getting an early religion and their growth-centric UBs, but I am fairly rapidly catching up. I've managed to keep poverty and illiteracy low by focusing on marketplaces, libraries/universities, villages, and even the occasional Great Merchant-founded town.
Realpolitik has also helped significantly, despite unlucky Civ spawns meaning that I had to look well into Eastern Europe in order to find any city states (Kiev and Riga). Having two alliances (as I currently do) results in equivalent bonuses to the Organized Religion tenant from Piety, which is a non-trivial advantage. If I had access to some of the Western European city states, things would be even better.
As I am playing on YNAEMP, I could not get a religion due to sharing the map with the Celts, India, a Mt. Sinai-owning Arabia, a Prophet-rushing Maya, and Egypt with a turn ~25 Stonehenge. If I had a religion, things might be going more smoothly. Still, I don't think that it is reasonable to balance Tradition under the assumption of a religion.
I noticed as I started that literally no other civ chose to start with Tradition (liberty comes in first, with 12 of the 19 discovered civs), despite several of them refusing to expand beyond their first 1-2 cities. In hindsight, I ought to have paid more attention to this, but hindsight is 20/20. Still, this being King, I remained optimistic that my abnormal choice wouldn't cripple me.
I am more or less correct. While Arabia leads in gold (after conquering much of Ethiopia during the Reign of the Camel Archers) and Mongolia in production, I am first in science by a small margin, and I am a close runner-up for gold. Egypt is holding close behind in science with just two cities, due to over half of the world being Muslim and their ownership of the Religious Council wonder. India is just behind them due to their immense population.
However, even with my rapid technological advancement, I find my cities outpacing my technological ability to provide city Combat Strength. In the late renaissance, Berlin is well into the high 20s, and I am suffering over 15 happiness from Disorder across a mere 5 cities. I find myself intentionally rushing techs which provide disorder reduction, only to discover that knowing a tech is insufficient due to my lower production relative to my Liberty-selecting AI opponents. It is worth noting that my cities are vanilla BNW-levels of invulnerable to outside attack, due to their immense populations, multiple defensive structures, and omnipresent, max-tech garrisons. However, this is insufficient to meet the ratio needed to avoid 3+ disorder unrest.
In short, I'm here to argue that tradition's supposed advantage – growth – is insufficient relative to the alternatives of pure production bonuses. In theory, more population results in more of all outputs including production, but the double penalty of specialist unhappiness means that it is inferior to simply taking the extra hammers from liberty. Buildings provide food, production, culture, and science in a fashion superior to pure population, and their malus (relatively tiny maintenance penalties) only threatens a single category (science) instead of threatening growth, production, culture and gold (and completely preventing golden ages from occurring), as unhappiness does. The happiness-producing capstone is, frankly, inferior to either Might's early stabilizing power (which double dips by reducing boredom) or Liberty's constant, scaling benefit.
I likely could've circumvented this disadvantage by selecting piety for its comically huge happiness bonus, which speaks to the power of the policy tree. I chose Patronage, instead, in the hopes of leveraging Realpolitik. Even with only two (poorly located) city state allies, Patronage is providing very real benefits in terms of culture, food, and commerce, but it can't get around my key difficulty of being unable to keep my population 'safe.'
I may simply be misusing Tradition's strength, or applying it to the wrong civilization (in hindsight, a City-State-Focused civ probably ought to select Might to get closer to desired allies or Liberty to ensure a sufficient supply of paper to produce various diplomatic units). However, it is quite frustrating to find myself risking first unhappiness, and then the unhappiness cap, by continuing to leverage my supposed advantage.
Edit: My net unhappiness runs between 2 and 6, due to luxuries, Patronage tree happiness buffs, a fair number of discovered NWs and generally high-quality cities. All other unhappiness factors run between 1 and 3 each, contributing to a total of around -25.