Ple-Sen
But the gameplay makes up for a lot. In OE, the things that had been grating on my eyes for countless hours of playing the fifth and third games were fixed.
And what exactly did they fix there?
The fifth game made war machines a useful skill, whereas OE... simply removed them, bringing back the dubious Ballistics from the third game.
Magic became better in some aspects, thanks to the addition of cooldowns, but the magic skills themselves plummeted in value. And on top of that, some overpowered spells were simply replaced by others that are no less overpowered — take Avatar (which they still can't balance) or the ice wall exploit!
Shooters in Heroes have always been dangerous and never needed buffs. Nevertheless, in Olden Era they... removed the limit on the number of shots (along with the ammo cart) and reduced the range penalties.
The specializations of certain heroes put any previous installment to shame. Forbidding your opponent from using an entire school of magic while you have max-level spells in it? Easy and simple — at least one such hero exists in every faction!
The economy in towns not only develops several times faster, but it's also easy to reach a state where the player can calmly develop all their towns, buy up all the growth, and spend the change on artifacts. In other games in the series, achieving that was possible, but not without effort.
Town Portal is now available to every hero, provided they have enough levels.
Alchemical dust adds nothing to the game. You either drown in it, or you upgrade the same creatures over and over. It reduces the variety of options, since only select units have active abilities without upgrades.
Special creature abilities now require focus. You gain focus either in long battles, or if you've heavily invested in it with skills. Not all abilities are equally useful. In the end, most of them turn out to be just pretty buttons you have no use for — focus will always go to one or two units.
In the fifth game, faction skills were diverse and reflected the factions' identities well: Knights upgraded creatures further, Dwarves had rune magic, Barbarians had magic suppression, blood rage, and battle cries... And what do we see in Olden Era? Boring stat bonuses for heroes in two factions. Two kinds of necromancy for two more. The Hive's gating, which wasn't even overpowered in the fifth game, completely gutted. And... just a couple of focus charges at the start of battle for the Grove, which half-heartedly tries to imitate Barbarian blood rage, but without much success.