Have you done the first class transfer quest yet? If not, you have many good options for that human fighter. Human wizards are far from being bad either. Just make necro or warlock. I would probably suggest warlock if you plan to play together mostly, they get a summon with a party buff that increases critical hit rate and damage.
fighters:
- HE = best archers, hands down
- DA = arguably best tank
- TH = right now seems to be the dagger of choice of 8/10 playrs
- Gladi = one of the best overal pvp chars. There is onlu one other dual sword class in the game but it cannot even be compared to gladis
- Used to be ubber in PvE and gimp in PvP, but poling got somewhat nerfed for pve and, in the other hand, are getting some really nice new pvp skills. They are still one of the fastest leveling chars and maybe they'll become good in pvp as well.
Mages
Sorcerer: the worst of the nukers, but still kick [censored].
Warlock = Many say are the best summoner I think its a tie with ES
Necro: mix of debuffer/summoner/nuker the proof that the game designers can do an excellent job out of a hybrid class if they want to. Got nerfed sice C4 but still a favorite in small scale pvp.
Bishop = best healer hands down
So except for sorcerers you can't go wrong with humans... if it is not the best class of the archetype it will be close enough
What they might have meant is that a duo of a human fighter and a human wizard would be a poor choice.
The mage-type DDs and melee-type DDs in this game typically aren't well suited to hunt together. A wizard will be able to kill a mob in 1 to 2 shots, from a range. A fighter, on the other hand, has to run up to each mob in order to kill it. A nuker, melee-DD would be a weird choice, as your nuker would knock out the mobs before your melee even got to them.
Plus, this game is highly buff dependent. If both of you played DDs and neither of you played a buffer/healer (or at least dual-boxed a buffer), then you'd really have it hard.
Some typical (and good) duos would be like a TH or Glad with a warcryer (or prophet or SE... not as good of a choice though), an HE with a prophet or a nuker with an SE. Those would all be good combos that could xp pretty quickly and efficiently.
If you are both brand new to the game and want to experience some different classes, I would suggest playing a couple of different duo types up till about level 30 or 35, till you can both decide which class-type you like the best.
Another suggestion would be that one of you could play the DD and the other could play the buffer/healer until 75, then you could switch, and let the support class have the chance at being DD on your subclasses. Getting to 75 and subbing, however, takes a while. So you both need to be happy with your class, regardless of what might happen at 75+.
Warlord + Bishop duo in the new rules can make a lot of XP very fast. Also will be welcomed to many parties.
Down side to Warlord is you have a pretty specific kind of fight. Warlords always want aoe (area of effect / multiple mob) kinds of combat. It's where they shine and they are a bit weak on 1 vs. 1 kind of mob grinds.
So Gladiator would be a better option there. If you go DA or Paladin + Bishop you will be welcomed widely into Raid Boss parties, which are tons of fun and very good for XP 20-40.
As others have said, Human is far from a bad choice - but the buffs is where you'll have a problem. If one of you wants to be a healer and/or buffer its a brilliant combo - if you both play non-buff chars, you'll need a boxed buffer, or other friends to play alongside.