Cast your mind back to 2013 when ITV’s Broadchurch and BBC’s The Fall were two of the best, most tense television thrillers of the year. Seems like a long time ago, right?

The second series of Broadchurch, which concluded last night, didn’t drop the ball as heavily as The Fall (which left many viewers wondering why they’d bothered watching in the first place). But from its disappointing opening episode – in which Danny Latimer’s killer, Joe Miller, pleads not guilty despite confessing to the crime in the first series – to its flat and frustrating finale, Broadchurch creator Chris Chibnall’s writing lacked the taut subtlety and the tight reins of the original, though the chemistry between Ellie Miller (Olivia Coleman) and Alec Hardy (David Tennant) certainly carried it along.

If Broadchurch is your only experience with Chibnall’s writing, look up his Life on Mars and Doctor Who episodes for some background. They show him to be a writer whose strength is creating testing situations for ensembles of strong characters, rather than a master of gripping plot.

Maybe that’s why there wasn’t really anything new in Broadchurch 2’s story: simply a fleshing out of the scraps from the first time round. As killer Joe was found not guilty by a jury, the point of his trial was seemed to be an indictment of the justice system, without any of the usual fizz of courtroom drama; and the Sandbrook case – mentioned in the first series but looked at in detail here – met with an ending that was not only implausible but frustrating, given that Hardy was unknowingly harbouring one of the culprits for the entire Broadchurch timeline.

But despite Chibnall's talent for character, the new roles introduced failed to make much impact, with actors of the calibre of Charlotte Rampling and Marianne Jean-Baptiste failing to get the best out of the limp barristers they portrayed (though Phoebe Waller-Bridge was rather gleefully horrible as barrister Abby Thompson).

So why did we keep watching? The strength of the original cast. Coleman and Tennant’s repartee might not have been as sharp as in the first series but they’ve made these characters their own, and their fraught friendship kept these eight episodes going. Alongside strong performances from Arthur Darvill, Jodie Whittaker and Andrew Buchan – not to mention Ólafur Arnalds’ atmospheric score and those stunning shots of the Dorset cliffs and coastline – they reminded us why the first season was loved by so many.

And they’ll be back again, according to ITV. Will there be a new story the third time round? Our money’s on recurring character Susan Wright – played by a truly creepy Pauline Quirke – as next series' baddie, though there’s still scope for Joe Miller to become a truly villainous figure, and not just the mute, snivelling defendant he was for most of this series. And Hardy, surely – hopefully? – will be back; after all, he might have got into that cab in the final scene, but we didn’t actually see him leave.

Broadchurch series 2 episode 8 finale aired 9pm, Mon 23 Feb on ITV.