If you want a system where magic is non-existent or rare, combat is discouraged and very deadly, and gods might exist, but never make an effort to prove it, then HM is a good fit.
...and why would anyone possibly want anything else?
Actually, I do believe you can play heroic RPG with HM, just don't start the PCs as per the character rules. Start them as veterans and give them advantages that 'by the book' don't get and you can have your Genin or Conan. There is also nothing in the rules to stop every second NPC from casting a spell, or from a priest perform Moses style feats. If you want 'high fantasy' magic then you might have to write the spell / ritual descriptions for yourself, but it can be done. Extensibility us built in to the basic system
Second try...yesterday's post isn't showing today.
I should have expected that answer!
For every type of play, there is one that loves it, and another that hates it. I once tried to get a Lionheart campaign going. No magic, although much superstition, lots of politics, bandits, crazy Scots coming over the border, etc. Couldn't get a single person interested. I am quite happy to do a historic fiction campaign, or an alternate world with no magic. But, if magic exists and the gods really are present, I need to have them out in the open. Partly it's the genre, but partly I am unable to fully commit to a world that has deities that do not manifest on occasion, or that has magic that cannot be used for the public good. Either campaign type is good, but this halfway meeting that has become more prevalent in Harn fanon just leaves me cold.
Every system points its players in a certain direction. AD&D leads to dungeon crawls. Hero System tends to lead to power gaming and min/maxing. I'm sure Runequest and GURPS aim players towards a type of play or genre. All can be used to play a campaign type very different than the standard, but it takes house rules and extra work, and still may not be optimal. Personally, I dislike house rules, and prefer to use a system already optimized for the style of play I want. I also like generic systems (Hero, Gurps), rather than specialized ones. HM is great if you want combat to be very deadly. If your typical campaign is the miller, reeve, a Peonian priest, and a yeoman beadle solving a murder mystery, then it is wonderful. If they run into 5 gargun or a couple Agrikian fighting order members, they should be scared.
My story is more along the lines of two knights, a forester, a veteren yeoman, and two Shek-P'var, all with significant experience and some with psionics, and they are regularly skirmishing with bandits, Solori, Lady of Paladin's soldiers, Ivashu, and gargun. I expect them to regularly beat twice their number of gargun with only minor injuries, because they are that much better at combat. I also expect them to get hurt badly when fighting certain key bad guys. Take equal parts of the Deryni, Sanctuary, and Tolkien books, and you have an idea of what I aim for. Now, I can do this in HM. But, I had already been using Hero for years when I first found HM, and Hero takes far less modification to get the style of play I need.
In my second storyline, the main characters are bishops, fighting order grandmasters, Shek P'var masters, and the King of Melderyn is a supporting NPC. Family connections to the upper nobility is assumed. It is heavy roleplay, leaning into the storytelling realm. Attributes, spell lists, and combat ability are not really important, because you'll be sending someone to do the dirty work. It's who you know and what favors are owed, and it is expected that the main characters will often be working directly against each other. The system make little difference, and I could be as happy with AD&D as HM. It's the setting and feel of the game that is important. The rule set is there to support the game, not be the game.