Inferno tactics.

Inferno has a big advantage on extra-large maps, without magic town portals; you jump between your cities. One hero can gather all the creatures and control a huge territory.

This is only the case if almost all the castles on the map are Inferno =))))
and in general... Inferno looks very good in a long game,
Utopias can be broken in 2 weeks.... in the 1st week, depending on the opponent, Cerberuses and Ifrits are built (and bought)
or Lords are upgraded + Demons. (and bought)
in the 1st case, with dogs, we eliminate most of the opponent (in this case, you don't need to carry Mogogs, because neutral mobs cut down what Mogogs attack with a ball and don't become a special obstacle for Cerberuses). We finish off the remaining ones with Ifrits.
in the 2nd case, we carry Imps (or if there are level 2 mercenaries, not Mogogs, we carry them)
Imps in groups of 10-15 (and we leave most of them under guard)
10-15 are thrown into the meat grinder (2-3 Lords per group make 1-2 Demons out of them)
we take the Demons away and kill them with our Demons that we bought in the castle, we finish off with Lords.
As mentioned above, by the 3rd week, you can get up to a hundred Demons. Which will already pose a great danger to the opponent. + at this time, the castle is being rebuilt, and by the 4th week, it is quite possible to buy everything (because the prices are not very high)
It is very convenient to find a +1 speed cloak... then Archdevils catch up with Archangels in speed and the first move is quite likely. Then cast spells and into the meat grinder =)

all of the above is IMHO