A bit above 1100 dota games, around 200 of lol and maybe 500 of hon here.
Personally I totally disagree with you OP. In my experience:
a) I have reported several DotA players, several reasons, and it's always nice to see bans when logging.
b) The only player I know/play with that has been on low priority/muted is a friend with rage quit issues and totally deserves it.
c) I would assume they have a filter to distinguish reports from people in the game from guys finding and reporting a random player, thus I am almost sure what you are saying is, pardon my french, pulled out of your ass. However it would be interesting to do an experiment, what do you say about mass reporting me (I go by Free Gold!! in DotA 2) and we can see what happens. Not sure if this is discussed in your link, the page gives me an error due not being logged in to those forums.
d) Really dislike the tribunal, it reminds me of: And it makes me never talk in LoL. In DotA sometimes I will tell the teammates when they are making a mistake, why and what better alternatives are, calling them retards in the process; in LoL I don't even say "GG, easy" due how totally bonkers and unpredictable the tribunal standards seem to be.
Personally I think both systems are crap, DotA should get more people involved in the report process and LoL shouldn't have crowdsourced it, especially because I am sure almost always it's the top 5% anal retentive players the one that volunteers for such a task. That said I like the DotA community a little better, maybe it's only because my ELO is quite higher there.
Edit: I admit to be biased also because I find DotA also way more enjoyable than LoL at all but the lowest levels, at which LoL really shines.