There are no guarantees (other than his contract money) with Raji.
The posters who called him a fat ass just wanted to see him get his butt into a GB huddle. Then to be glad the holdout is over is natural. No opinions about his ability have changed at all.
As for whether or not a DE can change the course of a game. There have been many DE's that had that ability starting with Reggie. (Disclaimer once again- I am not saying he is half the DL that Reggie was. Just pointing out that a DE can have a tremendous impact on the outcome.)
Likewise there have been many NT that had a huge impact on the game. When he was at the top of his game, the Gravedigger did a fantastic job. It was great to see him stop the run up the middle 3 times after the other team drove all the way down the field and had 1st and goal, 2nd and goal, 3rd and goal and then ended up kicking a FG. (A few of which were missed.)
Will he end up playing more at DE or NT? No one knows including the coaching staff. Will he be worthy of including his name with the all time great DLmen? No one knows. We will have to wait and see.