No he doesn't.
- The Assassin has save 5+ the Nomad Prince has save 3+ massive difference.
- The Prince debuffs 1 hero with 16" with -1 to hit, cast and dispell.
- He also buffs Sister of the watch, Wild rider, Wildwood rangers, Sister of the Thorn, Eternal Guard and himself (admittedly SotT and eternal guard don't benefit so much from it)
Damage output is roughly the same with a average 4 damage for the NP and 2 + 1MW for the assassin.
However with IronOak, the spear and a CP the NP is 2+ save 4 attacks hitting on 2+ wounding on 2+ rending on -2 and 2 damage. He's a beast.
Like I said the assassin is okay but for me personnally he is not the better general.