For all my time lurking the Codex, I've always wanted to debate octavius and Sceptic on M&M so I'm going to seize on this opportunity.
But exploration wise it was the best. And exploration was what the M&M games were about, or rather exploration was what the M&M games did much better than other turn based CRPGs.
It's true that exploration is M&M's calling card. It's the reason why it's not "Wizardry for babbies" as some would have it. They all do exploration incredibly well, but WoX (and 3) do it the best. The reason for that is because almost every tile is meaningful in some way, both in the overworld and in dungeons. In the overworld, it could be an NPC quest-giver or someone selling/giving away a super effective spell or skill, holes filled with treasure, people asking you riddles, caravans, fountains, etc. It's even better in dungeons, as they are stuffed with barrels with stat increases, secret doors, traps, puzzles, etc. Most of this stuff is in M&M6 too, but what sets WoX apart is actually the frequency of finding all this content. All the copious amounts of stuff is littered all over the place in WoX, giving you one serotonin release after another in quick succession, whereas 6 has a lot of down time. Not only that but WoX is not afraid of wrecking the balance and giving away huge XP rewards and stat increases--there's nothing better than getting a million XP out of nowhere. (Finding the most powerful plate armor long before you should comes close though, so the credit goes to 6 there.)
Another facet of enjoyment that you get from WoX's exploration is the way the skill system works. At the start, you can't enter a lot of tiles because you don't have the skill, so it's left there, tantalizing, until you get swimming, mountaineering, whatever. It's pretty much Metroid, and there's a reason why that subgenre is so addicting. It's a great feeling of accomplishment to reach areas that you couldn't before.
The loot system was also excellent.
No doubt. This is where M&M6-8 really shine, whereas it's M&M3-5's biggest weakness. The loot system in the latter is pretty much just "[modifying adjective] [armor piece or weapon]" It wasn't very exciting.
The inventory also deserves a mention. Fantastic in 6, terrible in WoX.
The bastardized combat system was weird, but didn't detract from enjoyment.
I beg to differ. I say the combat almost wrecks M&M6, it's so bad. Combat is clearly not M&M's strong suit, so why is so much time spent on fighting in M&M6? The combat was simple in M&M3-5 too, but you can get through fights much, much quicker. Combat was more like another wrinkle of gameplay for WoX; a vehicle to use your latest gear and spells, and another way to feel accomplishment. WoX wasn't about tactical combat, but it knew that, and so it took the backseat. In the case of M&M6, combat is front-and-center, and it's shit. It has all the tactical depth of M&M3-5 (read: not a whole helluva lot) but there are literally hundreds of enemies and all their HP is bloated. So a lot of time spent playing M&M6 is spamming the meteor and starburst spells, and then backtracking to a temple/inn. It's a serious flaw.
An easy fix for that combat is to simply lower the HP of enemies. If you're going to have tons and tons of enemies, make them quick and easy to kill; that way you feel like the shit when you're mowing down a literal army of them. The way it is now, you're spending more time in combat than you should for a M&M. It also hampers exploration--it's like a JRPG where you almost don't want to check around that mountain because there might be a ton of boring fighting behind it.
But the biggest hurdle for me to replay it is those retarded character portraits.
It doesn't help that all the people are ugly as hell. I did get used to them though, and I wouldn't trade them out for something different. Using real people as character portraits feels like a real Might and Magic thing to do.