Player rating for tournaments across all installments of Heroes.

Considering that our portal is quite new and therefore there haven't been many tournaments, nevertheless, a tournament like "Arena" was held for the second game in the series you can read about it here. And I think there will be more of them. We shouldn't give up on them...

No one is arguing with that. But this is a different type of tournament – Offline. In each stage, they play one-on-one until someone loses. Therefore, it would be appropriate to use your example about runners competing in obstacle courses over 400 meters and 100 meters.
If you are going to combine rankings from Arena-type tournaments and speedrun-type tournaments into one ranking, then why don't you combine all versions of the game into one ranking? Or do you only bring up the runner example when it benefits you? :)