Hospitallar is famous for their endurance and talent of defence. But compared with other two knights, they are two weak, even worse than the Aviz Knight. What a pity!
What's more,some units when they upgrade to a new type they will lose their traits just like the Aviz Knight and Templar receiving no defending or razing city bonus.
First, would you please stop opening one thread after another and post your comments in the right thread. (Questions in the question thread, remarks like this one in the playtesting feedback thread) It absolutely isn't neccessary to open a new thread for about 3 units.
The Aviz Knight is an UU, so you shouldn't compare a unit with them. (Exept the maceman) You should compare the Hospitaller Knight with the Maceman. Then, the Hospitaller Knight isn't less stronger. It has 5% less city attack, but 50% more city defense. (And no bonus vs infantry and heavy cavalry, but vs polearm, which is also less strong) But IMO, the city defense equals the bonus vs the other unit types.
It isn't rare that some traits will be lost by upgrading. For instance, in the normal game, the Rifleman has 14
and +25% vs mounted units. The Infantry has 20
and no bonus vs mounted units. They don't need the bonus because they are stronger vs mounted units anyway. If a Rifleman fight with a mounted unit, his strength will be 17.5 . An Infantry has 20
standard, so they don't need the extra bonus vs mounted units. The same way for the other units.