Part of the problem, I think, is that tall vs. wide needs to be balanced not just for human vs. AI but also AI vs. AI (since for most games, especially single player, obviously, there will be more AIs than humans); this is an issue because the human will always be better at waging war (potentially, at least, if he has spent time on "getting gud"). So while I would agree that an aggressive play style for someone who knows how to wage war effectively is going to make for an easier game on the same difficulty as a peaceful, tall, Tradition game, I don't think that's a flaw, but rather a consequence of the AI being better geared for competing with such a (human) player and of the aggressive player making a greater effort (in time, for example...lots of conquests means turns are longer and the empire is larger).
There is also a paradox here in that there are complaints about Warmonger Score increasing too quickly...this is exactly the mechanism that is supposed to punish the aggressive player over the peaceful player, after all, to reach more of a balance; if anything I'd advocate for aggressive expansion being penalized more through the happiness system, like making Puppets contribute a bit more Unhappiness (maybe go back to 1 Unhappy per 4 or maybe even 3 Citizens) or introducing a mechanic that makes warmonger score increase more rapidly for players who already have warmonger score (so scale added warmonger score according to existing warmonger score) or increasing the warmonger reduction from defensive wars as mentioned in another thread.
Artificially increasing the Supply of Tradition feels wrong, because the tools are already available for them to do so themselves (even early on: go for Terracotta, Great Wall, later Himeji...); if you skip those options and other options like defensive Pantheon/Beliefs and don't prioritize military infrastructure and units and expect to just ride the game out on the top of the Tech Tree all game long and think everyone else needs to just accept that you'll be peacefully taking the lead and snagging all the nice Science, Culture, Food, Religion and Diplomacy Wonders, then you can simply lower the difficulty, turn off victory competition and maybe even AI aggressiveness in general (I believe Recursive added such options, as well) and enjoy that kind of game that way. But in a normal game on a competitive difficulty level this kind of play style is supposed to cause significant problems for you.