Terraria (or Starbound) :)

Those are games that can keep me occupied for a while. :-P

Witcher 3. Have played nothing for months and still can't get enough.

Alternatively Master of Magic. Need to rebuild my skills there.

I'm a little biased towards HoMM4 because it was the first one from the series I played. It's fundamentally a flawed game because it was rushed out the door, the dev was going under and needed cash ASAP. We all know how that ends. The game is unbalanced, especially hero development, the move to 3D battles was not very well implemented and some of the changes introduced were badly received by fans of the series. The possibility to move armies around without heroes, for instance. I think it's a matter of perspective. Fans of the previous games were put off, and while I understand why I'm personally ok with it and actually missed it when I tried the older titles. Love it or hate it, I give credit to the devs for trying to innovate on the old formula. But where the game is strong, it's very strong. The world maps are gorgeous and beautifully animated (with sounds effects), the soundtrack is fantastic and the writing is top notch. The Order, Chaos and Death campaigns in particular bring back very fond memories. Let's face it, making a sequel to HoMM3 was a very hard job in the best of circumstances, and like I mentioned above the circumstances where far from good.

As for a game to take with me into a time bubble for 3 months: Minecraft, with a copy of the community wiki.

WoW, plenty of things to do for 3 months. Scratch that, plenty of things to do for 7 months, apparently, based on my playtime. That's 24/7 for 7 months.

Lack of proper balance is dangerous in a game like HoMM yes, and any game that gets it right deserves mad respect. AoW1 & AoW2 also managed to mess up the balance with hero development due to them eventually becoming mad powerhouses that can defeat entire armies all by themselves. Luckily in the campaign at least that doesn't really become an issue until fairly late into the game. Incidentally, the game with the best balancing that I've ever encountered is, beyond any doubt, Dawn of War : Dark Crusade.
I'll probably check out HoMM4 one day to see what it's like, but like I said, I'll probably go for HoMM2 first once I'm sufficiently done with HoMM3 (whenever that might be - if ever)

Total Annihilation or Total Annihilation Kingdoms. Very long story + tons of maps.

If I had 3 months to devote to it, I might actually be able to get into EVE Online. Or get back to playing The Secret World.

For an offline game, 3 months should be enough time for me to overcome motion sickness with Mount & Blade, or I could build modules for a NWN persistent world. Or play through all the Spiderweb Software games in my backlog. Try Crusader Kings.

Too many choices! :)

Well, this would be a perfect contraption for someone who has multiple medical assignments barraging them.... I would choose Satellite Reign, because it's been haunting me since I saw it on Kickstarter and now it's here I just need a break :(

My gosh I need a break...

Witcher 3, still havent played it yet tho I bought it. Trying to finish a series I started 1st, but I wish I had more time to just play games.

Grand Prix Legends. I would get it even if the time bubble lasted for 3 years. Alternatively, I would choose a 4x strategy like Master of Orion or Alpha Centauri or Sins of a Solar Empire.

Deus Ex. The game still holds up to this day.