Doctor Who needs to do right by Varada Sethu's companion

I've long admired the casting on Doctor Who, and the pairing of Ncuti Gatwa and Millie Gibson is another stroke of genius. Their chemistry is off the charts and they're both hilarious, but can darken the mood of a scene instantly if they need to.

At the age of 20, Gibson, who has put in years of work on Coronation Street, can seamlessly hold a brilliant episode together, as proven by 73 Yards – which RadioTimes.com readers voted the best episode of season 14. It's been an absolute joy to watch her as Ruby Sunday and I'm thrilled she'll be back alongside the new companion, played by Varada Sethu, in season 15.

But Doctor Who needs to do better by Sethu's companion. While it was a joy to watch Gibson, there are crucial elements of her story as a companion that we missed out on.

Take the early episodes, for example. The Church on Ruby Road gave me chills when Ruby saw the TARDIS for the first time because it's such a familiar and powerful experience for the companions to have. Then we have that glorious and memorable shot from The Devil's Chord, which shows Ruby and the Doctor raiding the wardrobe for '60s outfits.

But, beyond that, those sweet TARDIS scenes stop. For me, having little moments inside the TARDIS is what makes that relationship between the Doctor and their companion so strong. They might have a little day to day conversation, like an old married couple or a pair of pals who live together, instantly giving us a sense of what their dynamic is like. They might reference adventures they've had off-screen, expanding that world and giving us the sense that we've only seen a glimpse of their life together.

The chemistry between the Doctor and Ruby was so strong, but those little scenes would have made the world of difference, especially in an eight-episode season, which made Ruby's story feel a little short and rushed. For many of us, it felt like we'd only just said hello to Ruby before her emotional goodbye. Of course, we'll get to see her next season, but those little scenes could have gone some way in making her our eyes and ears for a little longer.

Then there was the conclusion to her arc in Empire of Death. It had all the hallmarks of an incredible companion arc, with clues and tidbits left throughout the season around the mystery of Ruby's mother – from Davina McCall being baffled at why there was no trace of Ruby's mother, to the Ambulance in Boom (Susan Twist) not being able to identify Ruby's next of kin, to Ruby's defeat of Maestro (Jinkx Monsoon), to the snow that fell every time Ruby thought of her mother. Slightly reminiscent of Rose Tyler's (Billie Piper) Bad Wolf story, there were moments in almost every episode that reminded us that something bigger was going on here.

Only that something bigger never really materialised, with Empire of Death revealing that Ruby's mother is... just a woman (albeit a lovely woman, played beautifully by Faye McKeever). Of course, there's a lot of beauty in Ruby's mother being an ordinary woman, and it certainly packs an emotional punch at the end of the episode when we see Ruby's family growing. But it was also quite the anti-climax. More than that, there are questions that haven't been answered (what about the snow?!) that make the story just feel unfinished.

As wonderful as Ruby has been as a companion, these seemingly small things have marred her legacy. Of course, it takes nothing away from Gibson's brilliant performance, but I would have wished for more for Ruby.

So, as Doctor Who gears up for season 15, I'm hoping it learns from Ruby Sunday. There are plenty of difficulties that came with season 14 that simply won't be there next time. For one, season 14 had to do a lot in just eight episodes. It had to lay the groundwork for a brand new Doctor and companion, basically re-launch the show so it would be enjoyable for a new global audience, it had a new and controversial release schedule, and it had to set up and wrap up a full arc for our companion, as well as dealing with Gatwa's schedule on Sex Education. It's certainly not an easy feat.

But, with season 15 and the introduction of Varada Sethu's companion, there are a lot of opportunities ahead. While we're meeting a new companion, the groundwork for the Fifteenth Doctor and for Ruby has already been set, so we can focus on Sethu's character and get that depth of relationship we were missing at points in season 14.

Gatwa will, hopefully, be more present, due not having to juggle being the Doctor with being yet another TV icon, Eric Effiong, anymore. And showrunner Russell T Davies has another spectacular actress to write for in Sethu – so, fingers crossed, he'll be trying something a bit different. There's no doubting that he's capable of a gripping, well-written and satisfying arc, as we saw it in his first run on the show.

The future of Doctor Who looks very exciting. Season 15 will bring us a wonderful TARDIS trio and, if the tidbits we've seen from when the show was filming are anything to go by, there are a lot of stories to look forward to. Plus, we get to welcome a new face to the Whoniverse. Here's hoping she gets her chance to shine.

Doctor Who season 14 is available to watch on BBC iPlayer. Previous seasons are available to stream on BBC iPlayer with episodes of the classic series also available on BritBox – you can sign up for a 7-day free trial here.

Check out more of our Sci-Fi coverage or visit our TV Guide and Streaming Guide to see what's on tonight. For more from the biggest stars in TV, listen to The Radio Times Podcast.