People criticize Merlin for all sorts of things including plot holes (sort of like a clot pole? lol). If you can do better, here's a template for a Quest for Gwen. Especially after Season 4. Write your own adventure:
GWEN QUESTS AFTER S4
These stages could fit nicely in either a single episode of Merlin or multiple episodes with one or two stages being a central theme. In other words, directly or indirectly, there would be a Gwen Quest. In which either literally or figuratively, Gwen completes the various stages. An outline for one quest (The Stages are Campbell’s while Mudock’s Stages are denoted by M):
Stage 1: Departure: Gwen is called to adventure, although she and Arthur are reluctant for her to accept. Gwen does and at her terms not his. Gwen would face the temptation that will lead to physical, emotional, or spiritual death. Here she would encounter a masculine force (like Arthur) that wants her to give everything of herself to him. But, she must be who she is and not someone who will agree to everything he says. And, returns his arguments by assuming masculine personality traits like logical reasoning and stubbornness. Yet, she must be willing to acknowledge she has weaknesses instead of denying that fact to herself by seeking those who can aid her in this quest. (M1: SEPARATION FROM THE FEMININE; M5: AWAKENING TO FEELINGS OF SPIRITUAL ARIDITY: DEATH.)
Stage 2: Initiation: Gwen crosses a threshold into a new, more dangerous world, gaining a more mature perspective. Motivated by her pure love for Arthur, she accepts and in doing so, she adopts aspects of the life she once knew. She re-encounters the representation of the Goddess and accepts those masculine aspects in Arthur she had earlier rejected in Stage 1 to heal the emotional wounds of her initial separation. This may be external in that she may give herself back to her family in some way or internal in that she becomes more independent. Either of which allows her to express maternal love again as she finds fulfillment and purpose. (M2: IDENTIFICATION WITH THE MASCULINE & GATHERING OF ALLIES; M6: INITIATION & DESCENT TO THE GODDESS.)
Stage 3: The Road of Trials: Gwen with Merlin’s (or other Supernatural guide) aid endures tests of strength, resourcefulness, and endurance as she encounters the negative aspects of the Goddess (these can be like the Ogre, the Dragon, and the False Knight). And to conquer those, Gwen must adopt the positive features of the Goddess. In doing so, Gwen comes to realize that she has lost part of her identity in this quest to succeed in the Male domain by her integration of the Masculine into her personality. (M3: ROAD OF TRIALS, MEETING OGRES & DRAGONS & FALSE KNIGHTS)
Now, she needs to go back and reconnect with the the feminine aspect of her personality: the female body, feeling, passion and emotion (Anima). to vanquish these obstacles in her path. This reintegration of the Goddess might also be the integration of the primal female, the 'Wild Woman', archetype --- impulsive, strong, passionate and comfortable with her sexuality using her female wiles and charm to get what she wants. (M7: URGENT YEARNING TO RECONNECT WITH THE FEMININE)
Stage 4: The Innermost Cave: Gwen faces a great trial facing the Goddess. In this confrontation, Gwen harness both the positive and negative aspects of the Goddess and triumphs thereby changing physically, emotionally, or spiritually as she accepts and integrates the old wisdom. Gwen might meet the “Grandmother” a guide, a benign understanding woman who has been maiden, mother, or crone who can heal the final split with the Mother Goddess. This is the encounter and acceptance of ancestral feminine wisdom. (M4: GAINING THE FALSE BOON; M8: HEALING THE MOTHER/DAUGHTER SPLIT.)
Stage 5: Return and Reintegration with Society: Gwen uses this new wisdom to help restore the land of Albion. She returns to Camelot to discover a different Arthur who embraces her as his equal in making decisions. While she has been discovering the masculine aspects and integrating these into herself, Arthur has become more tolerant, nurturing, and sensitive while still being at the core, Arthur, who encourages her to keep her masculine traits like self-confidence, rational thinking, and independence. As a stronger bond forms between them: Trust (M9: HEALING THE WOUNDED MASCULINE) and reaffirming their Love: (M9: FINDING THE HEART OF THE INNER MAN).
By gaining this success in the Masculine World and her personal world, Gwen achieves a synthesis of Male and Female personalities which are stronger than either alone as ts beyond duality - a singular being who embraces all within a circle of understanding. Arthur becomes more nurturing and tolerant while Gwen becomes more confident and comfortable with her sexuality and role as ruler. (M10: INTEGRATION OF MASCULINE & FEMININE). And setting the stage for the return of magic to Albion (the True Boon which is the Myth of the Eternal Return--- resurrection).