Do many people play Huge Deity games?

I'm under the impression that going from normal size maps to huge maps increases the difficulty by a fair bit.

I'm just wondering whether that level of challenge is consistently doable for many people at all.

I don't know about Deity, but I've done a Huge Immortal map and found it to be the same difficulty as a standard sized map. It was actually my fastest SV by 5 turns.

Why do you think bigger maps would be harder?

The only difference I see is that there is more chance of a run away AI who has twice the land of everyone else. But this is counter balanced by having loads more AIs to trade with and therefore more income from screwing them over.

The main advantage the AI has over players is its ability to expand and larger maps give the AI more room to expand.

Here's a fun idea: Huge Deity map against nothing but Hiawathas.

Oh, I'm not an expert or anything, I think that was the consensus for Civ 4, and I've seen it mentioned a couple of times about Civ 5 too.

Maybe it's a bit different in this, but in Civ 4 it seemed like beating up your neighbours is roughly the best plan, but on Huge you're spread out more and it's harder to keep pace with everyone.

Depends. If you're good at diplomacy, then larger maps are easier (you can play everyone near you off everyone else, providing a buffer, and ignore the far away civs). If you're bad/lazy at diplomacy, then it's harder, because you essentially have more competition. Also, you get more turns to position your military optimally for battles before they go obsolete, so "I need to take Civ X down" becomes much easier, while "I need to take out all capitals" becomes harder, since timed-pushes get out-teched before you're done with your conquest spree. You'll likely end up with a spaceship victory trying to go for domination.

Generally, for immortal (I haven't tried deity on huge), all victory conditions besides science are slightly harder (domination takes more time to capture all the capitals; diplomacy takes much more gold and esp spies to hold down city states; culture has you in a steeper battle for early/mid wonders for your 2nd/3rd cities).

Also, Tradition/Liberty is balanced on a Large map, favors Tradition on normal maps, but tips in favor of Liberty for huge maps, which makes wide-strategies easier/safer to set up on huge maps, which favor certain civ strategies (say, Arabia, Inca, Rome).