I think a lot of reviewers are being too hard on the series because of the big name. And true, if you consider this a part of the franchise - it does not fit it. Neither the games, nor the movies (both old and the recent "reboot").
But if you watch it without real expectations from the big name... It's not that bad. It feels like a teenage zombie flick or something. Not something that you would feel bad if you missed it, but it's quite good as something running in the background to keep you company. Like 6.5/10, maybe 7 some times.
I think this series would be much better, if they removed Wesker completely and it was rather something happening in the same world as the franchise (whichever part of it).