Mostly I remember that particular campaign being very long, me getting ridiculous levels and stats.
You collected all the permanent bonuses before ending each level, right? Even if you had the win you waited with finishing the level till you get everything?
I did that and remember the last levels being fairly easy (though far from Chronicles pushovers). On the other hand, I read that many people found the later levels very hard, probably because they didn't get the bonuses in previous levels.
I found the AB campaigns too easy, even on Impossible, and most could be blitzed since the AI starts fairly weak. Even the last one could be blitzed. In theory you can win it on day 1.
But I suspect the AI gets stronger if you dally too long.
Anyway, the less in-game time you use, the better your score, so that's an incentive to me at least. All that tedious mopping up just to make an already fairly easy game even easier is definitely counter-productive to me.
Personally I've mostly followed this chronology, written by someone at the RPGCodex:
"Might and Magic I: Secret of the Inner Sanctum
Might and Magic II: Gates to Another World
Might and Magic III: Isles of Terra
Might and Magic IV-V: World of Xeen (finish Cloudside before Darkside)
(Descendants campaign from Price of Loyalty)
Heroes Chronicles: Warlord of the Wasteland
Heroes Chronicles: Conquest of the Underworld
Heroes Chronicles: Revolt of the Beastmasters
Heroes Chronicles: Master of the Elements
Heroes Chronicles: The World Tree
Heroes Chronicles: The Fiery Moon
Heroes of Might and Magic I
Heroes of Might and Magic II: The Succession Wars
Heroes of Might and Magic II: The Price of Loyalty (Descendants starts much earlier, but ends around the same time the other campaigns take place)
(Dragon's Blood campaign from Armageddon's Blade)
Heroes Chronicles: Clash of the Dragons
Heroes of Might and Magic III: The Shadow of Death
Might and Magic VI: The Mandate of Heaven
(Foolhardy Waywardness campaign from Armageddon's Blade)
Heroes of Might and Magic III: The Restoration of Erathia
Might and Magic VII: For Blood and Honor
Heroes of Might and Magic III: Armageddon's Blade (except 2 of the campaigns, see above)
Might and Magic VIII: Day of the Destroyer
Heroes Chronicles: The Sword of Frost
Heroes of Might and Magic IV
Might and Magic IX: Writ of Fate
I still have problems fitting HOMM2 POL expansion into the timeline, but then it wasn't developed by NWC. I don't think there's anything in it that references any characters, events or places from any of the other games, including HOMM2 itself. Also, I've no idea if the HOMM4 expansions fit, and if they do, if they should occur after the base game campaigns, or before the Reckoning. The AB campaigns are largely independent but they all seem to occur after the main AB campaign, with 2 exceptions: Foolhardy Waywardness, which definitely occurs where I've placed it per its ending, and Dragon's Blood, which is giving me some trouble because of Clash of the Dragons. Clash of the Dragons, which definitely takes place after Dragon's Blood, mentions a King of Erathia, but there is no King of Erathia at any time after RoE. And finally, I lumped MM1-5 together at the beginning because it's simpler to do it this way than to try and figure out where they occur in the Enroth/Erathia timeline, to which they are almost completely unrelated anyway."
I wouldn't recommend playing Foolhardy Waywardness before RoE, though, since it's much harder than the extremely easy first campaign maps of RoE. The dissonance would probably be too weird.