Heh, I was afraid to put too much info lest people just go "Hey, wall of text! tl;dr"
Initially I just wanted to write one, maybe two passages simply to inform that such a game exists and is available
I'm pretty certain that during a longplay you can stack enough gold to afford a second hero of the same class, only it's hardly worth it, unless just out of curiosity
Then again, a limit on heroes is a noteworthy thing only if you compare the game to
HoMM, which is not absolutely necessary.