Hi, everyone. So I'm about to start Dragon Age, Origins, and I'm not sure which is the ideal party composition. I was thinking maybe making my main character a Dalish Elf to act as a rogue and finish with Morrigan, Oghren, and Wynne. Should I substitute any of them for Alistair and Leiliana? This is so confusing. I will play on normal and then when I get the hang of it I'll play on higher difficulties, but if anyone could help me out with the basics it would be very much appreciated. I just don't want to find myself in an unwinnable position because I developed my characters wrong. Thanks in advance!

Long time since my last game. But even on the hardest challenge almost any party is good enough (maybe the fighter archer is not that good).

So, your starting character is ok. The party combo sounds solid (strong meele, healer and offensive spells). Anyway, you should not worry too much. Those members can b e changed according what you are trying to do.

one tank, one healer, one locks and traps + dps | specials

Mage = heals, tanking, Dps
Warrior = Tank or Dps
Rogue = Dps + specials

any combo can win but some groups work together better than others, you will find Oghren dies fast if he tanks and Morrigan can Tank but she needs to be build for it overall your party will be great at range but have issues when things get to melee

Dragon age origins is an easy RPG even on "Nightmare" Level at least for me but for a good Party make up it depends also what Kind of character you Play:

Typical set up : a tank (Alistair) Shield tree , a Rogue ( ranged or melee) : you get Leliana (ranged and bard special) or Zevran ( melee) , 1-2 mages

so the Party Setup could look like this :

Tank (alistair)
Rogue ( Ranged) Leliana
Mage (Morrigan) which is a crowd Control mage
Yourself: You could Play : 2 Handed warrior , a second mage ( nuker mage does well with Morrigan but also with Wynne (support mage) , Melee rogue (Assassin with bard or duellist depends if you Play with Leliana or without)

Mages are very powerful in Dragon age origins since it's not for fun called Dragon Mage origins since they are so overpowered…

You can even Play Dragon Age origins on "Nightmare" solo with an arcane warrior: a Special mage Setup

So the game is not easy, it's easy if you play with mages.
If you don't like mages, it's difficult.