Things to enhance this great game!

[hexaae]

1. illusory walls (like EOB2), not just button ones. You can be attacked and cast spells through them.
2. different kind of secret buttons/bricks to move on the walls
3. lockpicking using found lockpicks (experienced rogue)
4. smart monsters will be able to chase the party and open simple doors!
5. you can Dismiss party members and recruit new ones found lost in the prison-maze. Much more interesting and vary. They can also steal things from your party while sleeping/resting and disappear (see the character Insal the Quick from EOB2)!
6. 'Attack All' quick button to attack all members together. No need to right-click one by one...
7. independent dual wielding swords/maces/axes to attack twice with a single party member who's got 2 swords and so...
8. underwater levels (like Black Crypt). You'll need magic breathing and artifacts to survive for a long time in this kind of maze. Will also add aquatic monsters.

[Roman0]

1. illusory walls (like EOB2), not just button ones. You can be attacked and cast spells through them.

I like this one. Would be good for secrets. Would be hard to find them, since the wall wouldn't be any different from any other wall.

2. different kind of secret buttons/bricks to move on the walls

Yes. Currently secret buttons seem to be too repetitive. If you find one, you know exactly what to look for if you want to find another.

3. lockpicking using found lockpicks

I don't see this happening, at least not in the current campaign. Every door has its key, and you have to find it. That's it.

4. smart monsters will be able to chase the party and open simple doors!

May be a good idea. I think it's hard as it currently is. Maybe an additional difficulty level?

5. you can Dismiss party members and recruit new ones found lost in the prison-maze. Much more interesting and vary. They can also steal things from your party while sleeping/resting and disappear (see the character Insal the Quick from EOB2)!

If it would be possible to find other survivors, for me it would break the sense of loneliness. Not a good thing. But that's me.

6. 'Attack All' quick button to attack all members together. No need to right-click one by one...

Too simplified. Read below why.

7. independent dual wielding swords/maces/axes to attack twice with a single party member who's got 2 swords and so...

How this, and point 6, would actually work? You'd attack with everything you've got? One selected weapon in one char's hand? What about spells? You'd have to select it (make it ready) to "alpha strike" with your whole party, cause I don't think auto casting would be such a good idea.

8. underwater levels (like Black Crypt). You'll need magic breathing and artifacts to survive for a long time in this kind of maze. Will also add aquatic monsters.

I like this one as well, only make it optional, or only some parts of the dungeon should be flooded. As you said, some magic stuff would be necessary for the party to explore such a place. If my mage doesn't know a spell that would help my party in this situation, or if I didn't find any water-breathing artifact, I wouldn't go there. I would probably leave out some good equipment, but it wouldn't be necessary to go there.

OT: Nice nickname, reminds me of this f*er

[hexaae]

1. illusory walls (like EOB2), not just button ones. You can be attacked and cast spells through them.

I like this one. Would be good for secrets. Would be hard to find them, since the wall wouldn't be any different from any other wall.

Only high rank mages will be able to randomly detect illusory walls passing by... and dispel magic!

5. you can Dismiss party members and recruit new ones found lost in the prison-maze. Much more interesting and vary. They can also steal things from your party while sleeping/resting and disappear (see the character Insal the Quick from EOB2)!

If it would be possible to find other survivors, for me it would break the sense of loneliness. Not a good thing. But that's me.

Nothing strange if you find in the whole game just a pair of imprisoned survivors starving to death and hard to find and rescue...

7. independent dual wielding swords/maces/axes to attack twice with a single party member who's got 2 swords and so...

How this, and point 6, would actually work? You'd attack with everything you've got? One selected weapon in one char's hand? What about spells? You'd have to select it (make it ready) to "alpha strike" with your whole party, cause I don't think auto casting would be such a good idea.

Just look at how EOB3 implemented Attack All...
And dual wielding would be great: you'll have to right-click on both hands to strike double damage! Just like EOB2/3 again...

[NightLord]

I quote all points of Hexaae. All attack does not convince me, but there may be, if one wants to use it then use it

[hexaae]

Attack All was actually just an idea from EOB3. The weakest of all improvement suggestions...

[Flying Ace]

it would be great if you could like be able to attack with one weapon in one hand and one weapon in the other. instead of it "darkening" and timing out both if you use just one

as for the invisible walls you mentioned sure, just please oh God please no rotating room puzzles