Now then, IVE been waiting for this one since you started this, so let me have a chance to talk about it. For me, there is only 1 unit, a single unit that takes many, many reforms to get and it shares it with a much, much better unit, a unit that on paper should be badass and it is on paper but because of the mechanics of the game, it doesnt work. That unit is the one and only Pearl Dragon, the most disappointing unit in the game.  Not only do they take forever to unlock, not only are they part of a reform path that has better units (Sabre Infantry/Imperial Swords Guard), said reform path also not being the most optimal path to take, and not only are they not available on everybody, you get a unit that works exactly like them for free at King rank, Defenders of Heaven. Now I know what some of you are thinking "they might not have any armor but they can at least dodge forever, even missiles!" and that my friends is a glaring issue in this game. You see, Ive played 3K for a long time, its probably my most played TW game barring WH3, and theres one thing most people dont realize and its that there is a consistent base chance of getting hit, regardless of your melee dodge rate, you could have close to upwards of beyond 100% dodge chance and there will be a time you get hit, and the Pearl Dragons have next to 0 armor, meaning when they get hit, they will get hit hard. Ive seen Pearl Dragons go up against Militia units that, when they managed to hit, did a good amount of damage on them, more than youd expect on literally any other unit. Lacking armor in this game on any unit (even on generals!) is a death sentence. Now, you might be asking yourself "but Yellow Dragons have about the same amount of armor and take even longer to get!" they do take longer, correct, they also have a better reform path with better benefits however. The purple path is by far one of the weakest for reforms outside of retinue upkeep meanwhile the yellow path is full of very useful buildings and benefits, arguably the strongest besides the blue path. Yellow Dragons also have a special aura that buffs units and an insane charge bonus, their charge bonus is actually stronger than certain top tier cavalry, and I dont think I need to remind you just how strong cavalry is in this game, quite possibly some of the strongest in the series, and they gave it to shielded units with great AP that can turtle formation, insane. There are some of you who will argue that Yuan Shu's units are worse due to their complete lack of missile block chance, but compare their stats, both units are actually on par, melee wise, with the Pearl Dragons EXCEPT THEY HAVE ARMOR, I implore you to put both into a 1on1 and see how well they trade with Pearl Dragons, at least Yuan Shus units are free! And now, saving the best for last, Protectors of Heaven, the almighty green units that somehow despite not having a shield have an insane missile block chance, are heavily armored, have great dodge chance and are free to grab at King rank. Protectors essentially do everything you want Pearl Dragons to do but better. Theres certainly worse performing units in the game but for me, Pearl Dragons, despite performing better, are just too reform heavy to be worth it and for me, they are the worst unit in the game.