All mana and movement cheating in online games doesn't really solve anything because the probability is low, and no one will bother to do it intentionally. But yes, it's a bug, and since it's a bug, it needs to be fixed, IMHO. Of course, it should be fixed in Heroes of Might and Magic HD+, not in the original Heroes of Might and Magic.
We will definitely be doing that. It often turns out that only a hero with 2k movement can reach between two castles/taverns, and you'll have to sit and wait until you can dig a path to connect them.