[color:"orange"]And what do you think about the option about the manual attack that with one click in the options menu is turned into an auto attack ? (as described in my previous post)[/color]

That would be fine if it can be done with a reasonable amount of effort and without effecting the game balance too much.

Contrary to your earlier comment, I think manual fighting might make things easier. If fights are decide based on the player's coordination and reflexes their character wouldn't need as much agility, for example, so could boost constitution more.

[color:"orange"]Do you think this might work or isn't that kind of auto-attack the kind you want.[/color]

In principle all that is required is a micromanaged fight system where you can choose to disable targeting and have the computer control aspects of your own character's fighting.

In practice, however, a micromanaged fight system implies a single character game with fewer, stronger opponents, alone or in small groups. A non-micromanaged fight system is more flexible and better allows for party members, pets, larger groups of opponents, etc. I think the choice of combat system will have a much broader impact than a box to check in the options.

[color:"orange"]If there would be henchman/partymembers, how would they follow you if you mounted a flying creature/changed into a dragon? would they also have flying mounts/Dragon Form? Or does this mean there will be no party members?[/color]

Reasonably I think a single dragon is more likely. If there is a party they may transform with you, you they may get left behind. If there is a single character with summoning dolls, the dolls may be necessary to the transformation, assuming it is due to some external power or artifact.

[color:"orange"]And if you would be able to change into a dragon, it would also afect the 'map-system'. Like if you use these 'gates', how are you going to make the borders inpassable, as mountains or trees can no longer limit a flying creature, it just needs to fly higher to get over them.[/color]

There can be mountains higher than a creature can fly; even with magical assistance dragons have wings, so must requires some level of air pressure to be able to fly. Some locations could be underground or underwater, preventing a dragon from entering. Some regions could have a magical barrier or a weapon effective against dragons, forcing you to enter as a human and do some sabotage before being able to enter as a dragon.

You may be transforming into a dragon only in some kind of spirit world or alternate realm, which may or may not be connected with Rivellon. In this case, if there is a one to one correspondence between the two places, perhaps areas in the dragon world that match places in the human world which you have not explored yet could be covered in a dense, impenetrable fog.

A separate (but connected) dragon and human world would make game balancing easier, though would make for less of a seamless world and could make the dragon aspect seem 'tacked on', depending on how it is implemented and integrated into the story. If everything takes place in Rivellon there would need to be limits on when you could transform or where you could go as a dragon. Perhaps you would only be able to transform for a limited amount of time at first, and that would increase as you leveled.