I think some bans could be more severe:
Innappropriate skins and links: A lot of kids play this game, and these skins can be really shocking or disturbing for them. Everyone knows this is not ok, it's common sense. If they do this, they just do it on purpose.
A 1-day ban is not enough. People can easily stop playing for one day, and they won't even notice the ban. 7 days is fair enough, if you ask me.
Abusing/Bullying: For most common toxic behaviors, 7 days is fine. Those typical, "you're a noob", "coward", or even insults like "f*ck you", "f*ggot", etc.
But sometimes, players can cross the line and say things like "kill yourself". This is when it crosses the line, I think when suicide is involved, bans should be way more severe. Like 30 days or a permanent ban. Suicide is not a joke.
Teaming / cross teaming: This is not as big of a deal as the two I mentioned above. Yet I think a 2-days ban is too little. As I said above, people can just stop playing for 1-2 days without even noticing the ban, or they can just say to their team "don't worry man, it's only a two-day ban". We can team up again, later.
2 days doesn't even feel like a punishment. 4 or 5 days would be fine.