I agree with what you said and would add a couple of other things I look for. First I want to see them play vs a good defense if they played Alabama or Georgia then I'm watching that game for sure, but also will watch a game against a less stifling defense because some times the talent gap between the teams isn't fair to the player. Also I like to see if they depend on the player as a play maker or do they go to him simply to keep the defense honest. I simply disregard plays where the player did nothing but run for the wide open space in front of him. Those plays are worthless for evaluating a player.no doubts. It takes a bunch of film study for sure, and even then, certainly no guarantees.
That's why I love watching the actual game film when those youtubers cut up the games and post every offensive play. Things like; how does that guy react to immediate penetration, what does he do when nothing is there, did he miss obvious running lanes leaving yards on the table, did he string things out to the sidelines and lose yards, or push forward and take the 1-3 yard gain, does he fall forward on those small gains that don't make the highlight reel, does he hold his own/is a willing participant in pass pro?. Everyone looks great on a highlight reel and usually those highlight reels show none of these. This guy shined, in MY eye test at least, when it wasn't an easy play. Much like N Harris and Rhamondre did last year. and Dillon and Taylor the year before, Jacobs and D. Harris the year before that. Its not foolproof by any means, Bryce Love, certainly had all those things, and many much lesser thought of Rb's also did those things, but of the more highly touted guys, those examples stick out in my head.