Help with Party Composition

[Glacial Frost]

Playing this game again, but always had difficulty making my party, so in my best efforts in trying to successfully complete a playthrough, heres my current party setup/plan (Don't have all the specialisations yet)

Player- Mage, Spirit Healer + Maybe Bloodmage, Mainly Support and a bit of DPS
Shale- For Being a Tank
Leliana- Using Bow, Ranged DPS
Morrigan- Shapeshifter, seems like fun so I'd like to try it out.

[SinCanDory]

I wouldn't suggest shapeshifting as it is hardly useful. Better use Morrigan with Entropy and Spirit magics powered with blood mage spec.

Crowd control is important in the game so it would help a lot.

In origins, I generally used my PC as off tank with high damage.
Had Alistair or Shale as main tank (depends on situation)
Leliana as bard/ranger (animals help a lot. Especially spider and bear) or Morrigan the way I mentioned above.
Wynne as healer.

Could carry the game on nightmare easily.

[ADEC Inc]

Two mages makes the group powerful enough that you can afford to mess around with shapeshifting if you want to. Generally the game is quite good about letting you form whatever group you like.

[Redman]

If using Shale, get the mod Shale's fixes from Nexus. That fixes the threat generation aspect of the tank talents which was never implemented.

Spirit Healer + Blood Mage is a solid combo. Get Vulnerability and Affliction hexes for your mage and use Blood Wound after you've cast them for a good bit on damage on your enemies. Don't bother taking more than Group Heal spell on Spirit Healer specialization as the rest are pretty subpar. If you want to remain support mostly then take the three glyph spells to help your party.

Shale - Start combat with Rock Mastery so Shale hits with Hurl Rock and Barrage and then have it switch to Stoneheart. Use Brilliant Nature crystals on Shale to increase health regen.

Leliana - Invest in Aim as soon as possible and have her equip aim speed gear. The DLC bow is pretty good for her and so is the bow you can get after you complete her companion quest which can be done very early on.

Morrigan - Shapeshifter is a waste for a mage but up to you. Swarm is the only good shape. Instead of shapeshifting you can have Morrigan do some spell combos like Sleep + Horror, Death Hex + Death Cloud and Tempest + Blizzard. Chain Lightning is a very good spell to handle 4+ enemies. Remember to get the ability fixes from Dain's fixes.

[Jan]

My nightmare party:

Player: Bloodmage DPS/Spirit Healer
Tank: Alistair
Bard Support/Archer: Leliana
Healer/Support+Spirit bomb mage: Wynne

Shapeshifting is bad imo. You only want one tank in the front row to bind all enemies. Other melee fighters are only in the way of your AOE spells. Bloodmage crowd control+DPS does the rest in combination with spirit bomb and mana surge to wipe out spellcasters. Or you play as rouge and backstab a lot.
But rouges are way better in Dragon Age Awakening. I finished it with my old bloodmage+Anders (Healer/Support)+the rouge dwarf(Tank)+ Nathaniel (Ranged DPS).
The new rouge skills make rouges better DPS characters than mages (you still need crowd control).

[Lust]

Main character - Duel Dagger Rogue human noble with lockpicking+persuasion+pickpocket for the stealing questline. Stock up on backstab passives/dodge/duel wielding and go to town. Preference is Assassin first then Duelist.

Alistair - Tank sword and board. Taunt, shield passives, warrior stuff etc. I like to get survival on him after combat mastery/tactics for map awareness. Templar and Champion skills.

Morrigan/Wynne - Spirit Healer+Arcance warrior (using the respec mod if using Morrigan as the healer to remove the useless shapeshift specialization for an 'evil' playthrough). Basically just for the passives and access to heavy armour so they can just survive a ton of punishment. Group Heal, Mass Paralysis, Healing, Mass Rejuvenation, Revive, Glyph spells.

The fourth I like to switch out depending on which quests I'm doing or if I'm playing as good/evil early game it's usually Sten spec'd mostly into the non-tanking two handed tree for Radcliffe and etc. Although he's probably the most annoying companion to bring along for a 'good' playthrough as he literally hates everything decent. But his damage is great.

Peak DLC for bank access. After that Mage Tower picking up Wynne+stat boosts and going with Morrigan for extra dialogue bits.

Usually go back to Radcliffe to finish off the kid quest (requesting mages help). By that point you run into Zevran so I pick him up and generally just use him for trap making/poisons since he doubles up on the MC playstyle and one Rogue is annoying enough to constantly need to move for backstab damage.

After that Shale DLC and sometimes use her since the rock throw is amazingly hilarious.