It is old problem though. All mathematics enthusiast AOE2 fans knew this problem. For instance, Samurai had +12 bonus damage + 33% attack speed to really counter unique units. On the other hand, Jaguar has +11 bonus and +4 damage from UT to countering infantries . Without attack speed, +11 bonus damage isn’t huge.
For instance, Elite Jaguar Warrior kill all non-spear line infantries in 3 hits (exception are E. Karambit Warrior and E. Shotel in 2 hits, E. Kamayuk and Obuch in 4 hits, E. Sergeant in 5 hits, E. Teutonic Knight in 6 hits) and die to them in 7 hits (exception are E. Shotel and E. Teutonic Knight in 5 hits, E. Berserk in 6 hits, E. Karambit Warrior in 11 hits). If you ask what is your solution for Jaguar Warrior, I would answer decrease food cost to 50. 50 food 30 gold is deserved cost for Jaguar Warrior. Jaguar Warrior would need additional buff unless Aztecs wasn’t top tier civ (I hope use unless correctly).
I don’t like that these forum guys are so influenced by pro players matches and opinions. For instance, Viper won a game with Hussite Wagon after that all guys started to complain about Hussite Wagon is OP. In reality, Hussite Wagon is trash. It is tank though but it has very little damage output and so clumsy (it wait a lot to throw projectile). Now, Hussite Wagon is same as Siege Ram. Hussite Wagon has damage output but it is very little. On the other hand, siege rams can destroy buildings. 50% damage reduction is unnecessary because even pros couldn’t micro units behind Hussite Wagon or old siege rams. Hussite Wagon answer a problem that never exist.
Now, Hera and Viper played some successful games with Longsword, thus forum guys started to say Longsword line became fine with last change. In reality, Sword line is still trash. With cheaper upgrades, going Longsword is much more affordable than Longsword but it still heavily countered by knights and crossbows, besides, crossbow and knight upgrades are still cheaper than Longsword. Best usage of Longsword is Longswords + Pikemen + 3-4 Monks (for big number of Knights) with siege rams. Vikings (Vikings has better farmers than Celts and more flexible civ overall thanks to insane eco bonus), Poles (Poles has best champion which is Obuch) Celts, Japanese (worst among these 4) are best civilization to execute this tactic. It is game finishing combo if you ahead in the game. Longsword still need additional buff though.