Vickers was ruthless and pragmatic (I always got the sense that her situation was meant to have been a 'what if' of Ripley having stood her ground and refusing to let Kane in). Not evil. Weyland, however, is shown to be egomaniacal and the type to want everything under his total control. He isn't the common sense type of Weyland who was merely understandably ambitious, as shown in the first of the AVP films. The company is more likely to be an extension of 'Prometheus'-flavoured Weyland's will.
And he's the guy who told David 8 to infect Holloway for shits and giggles - that was what placed him firmly in the 'evil' camp. There wasn't anything realistic which could have been gained from that. David 8 would have been much more likely to have yielded useful results by just continuing to test the stuff in the laboratory. No reason a small blood sample of Weyland's own human tissue/blood couldn't have been used on it.
The kind of Weyland we got in the first AVP film was more of a relateable figure and less of an 'evil Capitalist' stereotype, in the same way as Sigourney Weaver's character in 'Chappie' was. The latter gives me some hope that the upcoming film might go down such a road, which is infinitely preferable.
