Any YouTuber than has more subs than views automatically comes across as suspicious.
A 10k channel might have less views because they deleted or unlisted a bunch of videos, or they Sub4Sub'd (cheated the system).
However, as for average views, as your rely entales. A big channel will never receive 1:1 average views - subscribers. Since all channels of all sizes that matter have dead subscribers. Whether they be literally dead or just don't watch anymore. I know I'm subscribed to a few guys that I only want on occasion. A good rule of thumb is to be certain that absolutely every video you post receives about 10-20% as many views as you have subscribers.
So if you have 100 subscribers, you know you've been growing good if you can post any video with no tags and no advertising whatsoever and receive between 10 and 20 views. That would indicate that your subscribers who have subscribed have a tendency to come back and view at a later date, which is the purpose of subscribing. If someone subscribes for something other than to come back and view, then they are not worth calling your fan. That's one of the reasons that I vie against self-advertising, because you end up with so many dead subscribers.