Tigana has a number of nice concepts going for it, the idea of wiping the name and culture of a place from the minds of the world is a nice upping on simply levelling cities and salting the earth. The binding of wizards to a person of royal blood is also a cool idea waiting to be explored. 

The magically induced aphasia associated with the name and heritage of Tigana is a really interesting starting point but the author fails to capitalise on that potential thanks to repetitive, overly verbose and flowery writing that makes it a slog to get through the, rather limited, plot. This along with very flat characters and most of the plotting happening off screen really hamstrings the book the whole way through unfortunately. It's hard to care about a land and its plight when the main characters themselves don't really seem to care for much beyond the lost name and prestige rather than the people themselves. 

Women in particular are a real problem here with most of their function seeming to come as sexual conquests for the male characters whenever a plot element needs to be moved along. There's some very Rotfuss esque Felurian wish fulfillment writing going on at times and a lot really toxic attitudes towards women in general:

"I’ve been pleasant to you from the day we signed you on—and if you’re a professional you know that isn’t always the case in troupes on the road. If you must know, Marra, the woman you replaced, was my closest friend in the company. She died of the plague in Certando. I could have made life very hard for you. I didn’t and I’m not. I did let you know from the first that I found you attractive. I’m not aware that there is a sin in that if it is done with courtesy.’"

Dianora in particular, thanks to her predicament, is a real missed opportunity to write a deep and complex character, and she is about as close to one as Kay gets with this book but it falls short nevertheless with much of her dilemma in being torn between Tigana and Brandin left under developed. 

There's also the problem of the virulent homophobia early on in the novel which sours things massively and is completely unnecessary, as is the incredibly harmful allusion to the gay character being a paedophile:

"His father’s smile was so sad. Smiles are not supposed to be sad, Tomasso wanted to say. He had said that to a boy once, in a temple of Morian at night, in a room where he was not supposed to be."

"He might kidnap a boy from a temple of Morian, Astibar was saying, but plot against a Tyrant?" 

Creating a fantasy world and then adding that level of vitriol towards gay characters is a choice and since it offers precisely nothing to the overall plot or central arc of any character it just seems to be there because Kay wanted it to be as he even goes so far as to have one of the protagonists fearful to touch a gay character:

"Devin was impressed with the composure of the man. He was also aware, from the exaggerated courtesy and the undeniable sparkle in bar Sandre’s accentuated eyes, that although the fluting voice might be faked, Tomasso, in certain matters and propensities, was still very much what he was said to be. Devin accepted the glass, careful not to let their fingers touch."

Then there's the fact that one character, through the use of 'lotions and potions', assumes blackface for much of the book as well which just ugh...