Well in theory you would need to ask a player that has a equally geared Paladin/SK or Warrior(endgame) how they are doing Agro/Survivability wise, which i doubt you will find.
All have there pros and cons and i always hate the discussions who at the end is the better tank, all i can say all will get the job done don't matter what boss you speak about one might require a bit more healing there to get the job done but in the end it don't matter.
As a knight (Paladin in my case) its a bumpy road and i am sure during the lvling and gearing time warriors have it easier once they are geared and have access to clickies/spells it will be much easier from that point on.
Will it help to have now a Donator ?
Sure it does the clicky on the Paladin donator is nice it will help a tiny bit for for extra agro generation and helps with healing of some or all of the rest of the group.
Do you need the Donator Weapon?
It will help alot during the lvling and gearing process however endgame wise its not necessary since main agro generation will come from spells rather from the weapon (but can't realy beat the DPS and utility you get from the weapon with any other weapon).
Different Play style different perference.
Example A
A warrior main with a cleric and other chars that he would box would use group heals on heavy AE fights with the Cleric.
Example B
As a paladin i do mainly group heal myself for agro generation reason to take the pressure of the Healer and to heal the group.In this case i only use the Cleric to heal me and do patch heals on the rest of the group as needed.
Regarding Tanking Situation i think Warrior on single bosses have possible a small edge during AE tanking i think Paladins have the edge however(while i tank bosses i actualy prefer a few adds on me).