i don't think juggs need a buff. i've always seen them as a temporary thing - when you unlock them, that's a HUGE window of opportunity that basically allows you to steamroll the map. they lose their big impact once baseline troops show up in company strength with plate armor and high powered weapons, but nothing gets even close to their power at the medium tech level that allows you to build them. if you unlock them early enough and use them recklessly, you win the game. there will be noone left to research and build the troops that are powerful enough to stop them.

their guillotine axes are fine as they are. they are about 25% more powerful than other weapons of the same tier, which means they are basically an endgame weapon that is unlocked in mid game. the huge weight is justified since that turns them into a juggernaut-only weapon. it would be silly to have a 20 strength weapon at the same tech tier that unlocks 16 (?) strength battle axes for normal troops if it were not restricted.

You can design much tougher juggernauts. There are like 5 unique juggernaut traits, one of which gives +10 armor. You can also equip them with magical items and belts.

Iron Golems are like 5 times as expensive and much much weaker.

I think all the racial units should have end-game upgrades, and possibly early game versions added. Like how Resoln has 3 different spiders, one it starts with, one you get sort of mid game, and one that comes later (though their later version probably needs a big buff). I always play these games for the long haul and these racial units currently do nothing for late game diversity. Every faction, every game, it's just mounted companies in champion armor, with one of only a few weapon options. Armored Jugs and tier 3 golems unlocked with the champion armor tech should be a match for a company of champion armor clad troops, and just as/even more expensive.