I thought it was ok as a series ending, but not as an end to the franchise - which I believe will see at least one more series. Enough questions were left open that there's plenty of material for the story to go on.
But 'realistic'? Come on, this is - and is intended to be - high drama. We don't want 'realism', we want suspense, intrigue, opportunities for endless speculation, and we got all that. Actually, reading POBI, that is realistic.
Some questions I had at the end:
Who forged the Production Order authorisation to abduct Jo? Lomax has to be in the frame for that. In true Jed style, he's a clone of Dot Cotton.
Will Hastings successfully appeal his enforced retirement, or will his confession to Carmichael get him prosecuted?
Why did Kate do a runner with Jo after the confrontation in the car park? Was that a potential love story that was abandoned?
Carmichael was depicted as being very uncomfortable when she saw Buckells brought in again. She wanted charges against him dropped in E6, she said that anti-corruption investigations aren't a priority, and the pre-credit notes said that, if the application for public-interest immunity was granted, no evidence of police corruption would be placed before the court in Buckells' trial.
Why was Gail Vella killed? She was of no interest to the OCGs that Buckells was supposed to be working for. The only credible reason was that she was getting too close to the truth about corruption in the police. Osbourne must be in the frame for that.
Why did Kate go back to the medical officer after her chat with Steve? Is Steve likely to get suspended for not turning in his firearms licence? He was carrying a gun in the scene where they intercepted Jo's transport.
There's plenty more...