Hi,
FluentValidation is an excellent tool that keep us from using DataAnnotations' Validator's decorators to achieve the entity class keeps as is, a just POCO class. The pros of this lead us to those developers, like me, that focus its backend (entities) development in Database-First processes, to lose decorators applied to the entity or model view class in every change made to the Database rather than the entity class, FluentValidation give us a better control of the validation rules, separates the validation from the entity class or view model class, testing is easier than DataAnnotations and support client-side validations. As far as I know, FluentValidation injects Data Annotation under the covers.
It would be great if you consider to take advantage of the integration with this tool in your route map.
Thanks