Post how you would've done the finale (part 2 and/or part 1) in the comments below!! This is of course pretending the budget was waayyy bigger :D and more screentime..
I will cover how I would've done part 2.
- The war in Camlann continues. It's the same epic action but twice as much magic and a few more scenes. Also less reused shots of Arthur kicking and stabbing Saxons. Maybe a few less matrix slow-mo shots (they were still really cool) so it looks less reused. We also get to see more Gwaine and Leon fighting individually.
- Aithusa flies across the sky and Mordred and Morgana are standing on the cliff above where the war is happening. They chant a spell, and the sky goes a more fiery red like in the vision. Fireballs then start raining down from in the sky, killing many knights. Mordred then goes down to join the war.
- Emrys is still galloping along on his horse towards the battle as you'd expect, returning from the Crystal Cave. We see him chanting a spell on horseback and charging his staff up with the all mighty lightning, as he approaches the war.
- A group of Saxons (like they do) all charge at Arthur and the lightning blasts them away. We actually see the lightning hit them rather than just a flash then they get thrown away. The ground reacts to the lightning bolt and sand is shot up. More variety of shots of Saxons falling and being hit.
- We see a shot of Mordred looking mortified to see Merlin/Emrys is alive and he takes cover somewhere, not wanting to mess with Merlin (after all he is the Dolma). But he wants to still take the opportunity to strike Arthur.
- Morgana screams EMRYS! and Emrys strikes her with a bolt, but she reflects it with a shield. Emrys uses his staff and the bolt that reflects reflects again, with more bolts this time. He raises the staff and shoots a lightning wind. Morgana dodges, and it hits the cliff, rocks flying everywhere. Morgana then seems to disappear, then appears again on the same cliff as Emrys. She throws rocks at Emrys. Emrys dodges them, falling, and Morgana comes at him with a knife but he strikes her again. The shot is powerful and some Saxons/knights nearby go flying. Morgana then shoots a beam of lightning straight out of her hand but it sends her back a bit and she slips and falls off the small cliff, knocked out.
- Aithusa flies over and he chants a spell to get rid of her
- A moment later, Emrys is standing over her. He is looking at all the destruction- all the dead knights and fire. He says to Morgana is this really what you wanted? She resists saying what she said in the vision. Obviously the visions aren't completely accurate (as we know). She tries to strike Emrys again but he restrains her arms, pinning her to the ground.
- At that moment, Mordred approaches Arthur and stabs him. This happens to be nearby to Morgana and Emrys (on the other side of a large boulder or hill). Merlin senses it and runs over to see Mordred standing there and Arthur on his knees. Mordred looks behind to see Emrys, and as he is looking Arthur stabs him. We then get that last epic smile- Mordred is relieved he got his revenge for Kara and it's all over. He collapses and dies. Merlin goes and picks Arthur up, who has gone unconscious. Merlin then notices Mordred's body disappear, and he then looks behind to see Aithusa carrying an unconscious Morgana and Mordred on her back. As she is about to fly, Kilgharrah suddenly lands and is furious at Aithusa.
- The two fight, leaping and slashing at each other, and exchange fires. Aithusa is fast and Kilgharrah is weak and limp, but is still stronger and manages to throw Aithusa quite far. They both then make one final dive, Kilgharrah bites Aithusa's neck and Aithusa bites his leg. They both fall and Aithusa is crushed and dies. Merlin's ageing spell wears off and he goes and says his last words to Kilgharrah as he passes on. Very emotional scene. Kilgharrah tells him the golden age has come to pass and to let Arthur go, obviously Merlin refuses and insists on going to Avalon. Kilgharrah smiles and passes away. Merlin goes back to Arthur, and in the distance we see a Saxon taking Mordred's body and an unconscious Morgana going away on horseback.
- Merlin meanwhile is taking Arthur to Avalon. Gaius comes and meets them then leaves again to Camelot, assuring Arthur is safe in Merlin's hand. Gaius meets Gwen not far out (who followed Gaius) and Gwen guesses who the sorcerer is, and Gaius tells her Merlin's destiny and how Arthur is the once and future king. So we get to have confirmation Gwen knows who it is.
- The piece of sword embedded in Arthur's chest is towards the tip rather than more in the middle, it makes more sense. Mordred's burial scene goes as normal.
- To be honest I wouldn't change Gwaine's death. There had to be deaths and for the sake of realism good-looking favourites (Gwaine had sort of turned one-sides/annoying IMO anyway) shouldn't always be kept. Plus Morgana has for some time intended to kill Gwaine and finally her threats come off. It was a chilling and bold thing to kill Gwaine, I liked that dark and bold aspect.
- So the Eira arch would continue, Morgana goes to the wrong spot, Eira is killed by Gwen, Morgana ties Percival up (he lives) and kills Gwaine, and Morgana catches up to Merlin and Arthur. But this time, Morgana doesn't stall and her death isn't too easy. She does indeed knock Emrys out and taunts Arthur but watches her back for where Emrys went. Then, Gwen appears as a distraction to Morgana and asks her what she has become and basically goes off at her for what she did. She then says Camelot has not lost, whereas Morgana has lost everything because of her actions. Merlin then approaches again (he is a bit worn from the journey with Arthur) and Morgana is about to make a tree fall on him when Gwen tries to attack Morgana. Morgana is about to finish Gwen when Merlin has seemed to disappear, but then comes from behind a tree and stabs her with Excalibur.
- Gwen says her final goodbyes to Arthur. A tragic scene with Arthur dying at Avalon. Merlin returns to Camelot and is amongst the knights, in a new outfit.