I think we all knew from day one that the tournament was missing booths or separating walls, but nobody said anything until these incidents started occurring 
Personally, I think Riot is being too lenient. The fine should at least be much greater, and should definitely scale off total tournament earnings and not just current earnings. Also, all cheating teams should be fined, not just Azubu - all of them broke the same rule, so it makes no sense that only one team be punished.
That said however, any action beyond a fine would not be possible at this stage.
To those calling for Azubu to be disqualified:
If we take the matter based on principle, EVERY TEAM that looked up should be punished equally. As people have written many times before me, cheating is cheating, regardless of the end result. The rules expressly forbid looking anywhere but your own screen. Five teams broke the SAME RULE. So if Azubu got a DQ, I would expect TSM, TPA, WE and IG to all be DQed as well. Imo, this would be the worst outcome.
To those calling for a rematch:
This would be the fairest (and most entertaining) recourse, but again, not feasible at this point. Given the already enormous delays due to connectivity issues, one can assume that Riot no longer has the time to organize and hold any formal rematch. They are renting the venue; they don't own it. Riot probably would have had rematches if time constraints weren't a factor.
Ultimately, I'm not going to let this sour the finals. I'd rather watch one more amazing bo3 (with the stage setup issues rectified of course) than have five teams disqualified and a flaccid end to the tournament.