Way back in the day I played a lot of Heroes of Might and Magic 3. It is a great game but of course it has many quirks and things that might be called design flaws depending on your point of view. One thing that defined it was the fact that battles and decisions in the early game were so incredibly critical to lategame success due to momentum. In the early game you would often be in situations where playing perfectly would save you half a dozen of your units and playing reasonably would lose them and this would snowball as the game went on - having those units would mean that in the next battle you lose only 2 units instead of 6, and the next battle you lose none instead of 10. Every time you lose any units you lower your maximum army size permanently and that means in every battle that follows you do less damage and will take greater losses. The main problem with this is that when you play the early game perfectly the late game ends up being really boring as you march around the map with an army that has been accumulating since the start of the game and which cannot possibly be stopped. It still takes a few hours to clear out every single opponent but nothing could happen that could stop your victory.
On the other hand even small losses would slowly chip away at your army's strength over time and a bit of bad strategy or bad luck in the early game could wipe you out easily if the scenario were challenging. I don't think that the early game should be irrelevant of course because that would make it rather boring but it seems like in most hard scenarios the player ended up spending the last half of their playtime demolishing trivial challenges. Recently Sthenno told me about a very similar game called Kings Bounty: Armored Princess that solved this issue very neatly. (I find the Armored Princess title to be utterly hilarious... who thought that up?) The solution involved limiting army size based on characteristics of the hero. In HOMM3 any hero can lead any amount of troops so losing troops at any point permanently shrinks your final army but in Armored Princess that isn't the case because army size is capped by the leadership score of the hero involved. This means that you still have to win every fight and you can't go around losing *too* many troops to each battle but losses in the early game can be made up for by luck or strong play in the later stages of the game. This mechanic balances out the critical points in the game much better and allows the designers to create significant challenges in the later stages of the game that cannot be trivialized by good play in the early going. In addition it prevents the situation where a player does badly in the first hour of play, plays well for 3 hours, then discovers that he simply cannot win anymore.
HOMM6 is coming out fairly soon and I look forward to it with much trepidation. HOMM3 was a treasure, despite that it did have a few flaws, but HOMM4 had really terrible gameplay and was quite a failure. HOMM5 was basically a reskin of HOMM3 but with huge problems with AI pathing to the point that large and complicated maps were impossible - the game just locked up your computer. Had that not been an issue though HOMM5 would have been a tremendous game and very enjoyable. Here's to hoping that Ubisoft figures out the magic formula: People don't want that much innovation. Just build HOMM3 with better graphics and more cool stuff and people will love it and pay for it. Mindless summer blockbuster films prove this over and over... you can add nothing of substance to the genre and just rehash an old classic as long as you rehash it *well* and people will shovel money your direction. Just ask Madden Football, NHL Hockey or any other 'prettier and with some new toys' game franchise!