Hey EGBE0523, that would certainly be a bad move, as you say TUI is not generally a well know entity as a brand in the UK, though I suppose those in Germany appear to have recognised this by excluding TOM from the 'respray'.
As far as the retro thing, I think that is a great idea, the Air France retro a/c of recent times look absolutely great, and Cimber Sterling have done the same with their B738's, so why not?? Though, as we know its not just the livery thats changed since BY.