Whilst Brewster hasn't set the world alight, he's been playing in objectively one of the worst performing teams in football history. Judging him based on this isn't exactly the best proxy of ability. Whilst few and far between there's been the odd spark or glimpse of his potential ability.
Ultimately, 20 year olds who are scoring in the Premier league regularly or playing really well aren't going for £20m to a relegation threatened team. Also, a common narrative seems to be, he cost £20m therefore he must be very good. The amount paid has absolutely no bearing on a players ability.
Hindsight suggests a more experienced / established striker would have been better for this season - but the list of obvious and achievable targets isn't exactly long? The fact that he probably wasn't what we needed this year, and maybe a midfielder or LCB would have been better, this isn't his fault!
Like it or not, he's been signed for the long term, and if we go down and he replicates his Swansea scoring record again - these days £20m is pretty much the going rate for a 1 in 2 striker in the Championship (Watkins, Maupay, Mcburnie etc) and it becomes a 'fair' price.
Short version, judge him in 18