Super Heavy Armor are like Mountaineers, excel in smal number of situations. Some other units such as infantry and medium armor are generalist, they don't solve hard situations like Super Heavy Armor or Mounatineers but they are more flexible.
I disagree completely.
Mountain troops, both historically and in the game, are useful in a wide range of circumstances. In fact, they are even better than INF in certain categories in game terms, while losing out on the anti-tank capability (except for French and Italian elite units). If it was feasible from an IC and leadership standpoint, you could make entire armies composed of MTN (I've done it as China, except for garrison forces). It's the same with MAR. If cost wasn't a factor, it would be superior to plain infantry in 75% of situations, with the other 25% of situations covered by adding some AT, TD, or ARM. (I like giving the Marines their Shermans.)
Do keep in mind that in HOI3, MTN and MAR had terrain bonuses on several types of terrain. MTN have bonuses in woods, forests, hills, mountains, and arctic. MAR have bonuses to amphibious attacks, but also jungles, river crossings, and swamps.
In real life, the cost of creating, training, and equipping these special infantry types (along with the stricter requirements for recruits) limits their creation. But the limiting factor isn't that they suck in some situations. The limiting factor is cost. Remember: you can always add AT guns or tank destroyers to back them up in the event they come across tanks. (I do it sometimes as France. Good luck pushing through the Italian border with MTN/AT divisions holding the mountain passes. They eat Panthers for breakfast, then take a break for lunch with nothing left to do.)
SHARM have a much narrower field of application in both history and gameplay. The situations in which it makes sense to employ these tanks are few and far between. There are few offensive situations that favor their use. Due keep in mind that if you are thinking that you need the
Maus to break pillboxes and fortifications, you are mistaken. The StuG III was great for doing that job, and cost a fraction of even a King Tiger. It was also useful in more than one role.
And the Germans loved their StuGs. On defense, it can hold a position, but only so long as it isn't being bombed or overrun with infantry. And if you need to retreat or redeploy? Well, that's too bad. They are so slow that you are more or less committed to holding in place. Hope you brought a deck of cards; you're going to be defending that piece of terrain awhile.
This also even assumes you can supply, fuel, and keep them repaired. MTN may not be the easiest troops to train or equip, but they are more durable on a long campaign than SHARM.
From a game perspective, I can't see them being that useful in open terrain despite being a tank. They're too slow. I know they are, because I invaded Europe one time with an entire US Army composed of MAR/MAR/MAR/SHARM. It was ridiculous to watch my Marines standing around on smoke breaks while they waited on the slow SHARM to catch up. (Why did I even train my Marines to run three miles in 18 minutes if it takes the T-28 an hour to do it?) It was the slowest victory
ever against the Axis powers. I could have been fiddling in Berlin months earlier if I had faster tanks. And SHARM wouldn't have helped Germany even the odds in this situation anyway; I had air superiority, so SHARM brigades would have just been big targets for my TACs. That's assuming I was fighting fair; if I was being a punk, I would have logistically bombed the SHARM and then laughed at them as I attacked them.
Super heavy tank would be Maus and the like. King Tiger is NOT super heavy. KV 2 even less.
I would agree with you, although I wonder if more reasonable designs like the E-75 will count as SHARM or HARM.