I think currently there are 5 units competing for that spot. Mangudai still should have the edge, but the other 4 aren’t that bad either, at least in their specific maps:
Janissary
Conq
Huskarl
War Wagon
And the obuch deserves a honorable mention, too.
Edit: looks like we have some trolls here… Jag got a vote xD.
There are several great UU’s, but nearly all of them require support units. I voted War Wagons because you can spam literally one unit and take down everything that isn’t a castle (or a few other counter UU’s).
considering how weak they are too archers i’m not that concerned. they don’t see that much use, especially in team games. and +8 is impossible by the way. they don’t get blast furnace.
Imho Leiciai are not even THAT weak against archers, since you need only 2 relics to 2-shot arbalesters and 4-shot HCAs. As a matter of fact, they’re like a buffed heavy camel that costs more food and less gold.
They suffer from the same problem that afflicts a lot of other melee cavalry UUs though: they’re heavily bottlenecked by castles.
To kill 30 FU paladins you need at least 25-26 Leiciai (with 2 relics), if you want some margin.
When the numbers become bigger you simply can’t keep up with Castles. I’m obviously talking about team games.