Nice summ up. But you missed a "few" things
At balance: "Not enough information to go by, but it seems a lot of Heroes are played only very rarely."
My question is, why do you compare the balance part, if you´re lacking of information about balance in HoN?
If this is your HoN account, it explains most of the rest of your "critic" (hm, I´m missing the "inser link" button currently, don´t know why):
If I´m mistaken, sorry.
The graphics of Demigod are really great (if you have a good machine). HoN offers some neat effects for lower hardware, too. But in high settings, Demigod is really nice
But I don´t see the factor of mistakes.
For magnitude i have just a short comment:
HoN offers a very powerfull map editor right from the beginning, you´re even able to create first person shooter stuff with it (confirmed by developers in forums etc.)
Demigod is peer to peer. HoN is client<->server. The result: People got kicked in Demigod if they got a ping higher than maybe 350ms. In addition to that you need a high upload speed in order to get all those tiny packets to your game mates.
In HoN, you only communicate with the server (if you´re playing CS or something like that, just imagine you´re playing CS ). So your latency will be near 0 (compared to WC3 and Demigod), your ping is not as high as in Demigod and you don´t need this amount of upload speed. A nice feature of HoN: You´re able to rejoin games which are in progress.
There have been dozens of discussions about: "Demigod vs. HoN/LoL/DotA/Pacman".
You´ll like HoN if you want DotA 2.0
You can´t really compare Demigod with HoN or Dota or anything else because Demigod is only based on the idea of DotA (and a few other games). Stardock and GPG are doing a very good job in getting the community involved into the development of the game.
I mean, I don´t compare Quake with Battlefield too