Talawa Theatre, Britain's leading black theatre company, first staged King Lear in 1994. To mark its 30th anniversary, artistic director Michael Buffong returns to the play with Don Warrington in the title role.

This is not an all-black production, nor is it a pointedly black reading of the play. In fact, it's ultra-trad: an empty space staging played in passable period costumes. If any Shakespeareplay can handle that, it's Lear, with all its nothings and nakedness, but goodness it's dry and dated.

There is a point to this – Buffong is staking a claim to British history. A black King of England, even a fictional one, asserts ownership of this country. Seeing black men in medieval cloaks and tunics, women with braids built up into raised cornettes, challenges the textbook image of those times. You could point to a Game of Thrones aesthetic, backed up by Lear's divided kingdom, but the style is really old-school RSC.

That's the big problem, though. This is mightily old-fashioned, gruellingly so, and played at a geological pace to boot. It's sword-fights and alarums and flaming torches. Everything is generically olde England. Men chomp of grapes and letch at wenches. There's even the obligatory Bloke Eating a Chunk of Bread In The Background. None of it rings true. These aren't real people. They're acting tropes.

It reads better than it plays: a treatise on power and the loss of it. Warrington's king is majestic to start: his voice thunders with authority; his subjects kowtow to his commands. In dividing his kingdom, Lear gives that up, only to hanker after it later, and Warrington is at his best on the wane, demanding then pleading for his private army. His daughters – Rakie Ayola's stern Goneril and Debbie Korley's wavering Regan – and their husbands grow into their supremacy and abuse it.

Power is given, not earned, but how people cling to it. Against race, that becomes a stark critique of the (white) establishment's refusal to yield and truly embrace equality.

Buffong equates powerlessness with madness. Lear loses his wits after his status. Warrington's growl becomes a burr, until volume finally deserts him in those final five o's. Alfred Enoch's Edgar adopts Poor Tom's insanity (and loincloth) to hide in plain sight, deemed harmless by soldiers hunting for him, and Miltos Yerolemou's whitefaced Fool – the ying to Lear's yang – has a lowly lunacy. What never materialises, however, is the freedom and beauty of that.

After Gloucester's blinding – so violent an optic nerve ended up in the front row – a servant (Sarah Quest) bandages his eyes. The tender moment is singled out with a spotlight, but it's a mark of Buffong's direction that she fails to wash the wound. That lack of detail runs throughout – almost every performance is marred by it – and it's fatal. It makes for monotony and, if Warrington's Lear is anything it's that. He doesn't stretch the part to its extremities, not so much scaling Mount Lear as flattening it.

King Lear runs at the Royal Exchange Theatre, Manchester from 6 April to 7 May, after which it transfers to the Birmingham Repertory Theatre from 19 to 28 May 2016.