This is all just coming from my personal opinion and experience
1. I personally don't think an adventure game has to be original to be good. Although originality can make for a great game. Many of the LucasArts classics I consider to be very original. Games like the Agatha Christie games and Sherlock Holmes ( the latter of which I only played "The Awakened") aren't original concepts, but they are still fun to play, and if you were already a fan, then there is that added appeal. About complex plot structures and symbolic meanings in games: well I can't really think of any adventure games that are really complex and hard to figure out the meaning of, off the top of my head. There are certainly games out there which really have a powerful impact on you and are meaningful to you personally. For me games like that are The Longest Journey, Dreamfall, and Grim Fandango. I loved those games for their epic feeling.
2. I like both puzzle solving and talking to characters. Aside from the plot, they are my favorite aspect of adventure games. I don't mind mini-games if they are simple and don't detract from the plot. Example of a mini-game gone wrong: the hacking puzzles in Broken Sword 4. They were difficult, there was too many of them, it did nothing to move the story along, and the worst part was that some of them were timed.
By default I prefer if there isn't combat in adventure games, but if there happens to be, at least keep it simple. The combat in Dreamfall, simple as it was, was also terribly made, and like the hacking puzzles of Broken Sword 4, didn't move the plot along.
3. Point of view has never really mattered to me. I play both first and third person games. Control wise I believe point and click mouse control really works best for adventure games. It has worked well all these years. I actually don't mind keyboard control, but point and click works the best.
4. If I go to replay a game it's usually because I really enjoyed it, rather than trying out different alternate paths. I guess I'm too lazy to go and try other paths. They are certainly a good aspect to have as long as there are not too many alternate ways of doing things. Culpa Innata had so many alternate dialouges you could choose with characters, that it would take several replays to get them all. To me, that's just too much. I actually only stuck with the one path every time I played Fate of Atlantis. Although I wasn't aware of the two other paths until a couple years ago. I never played them. Just too lazy I guess.
5. Why do something more than once if you don't have to? I guess if it really is fun, then that is a bonus. I did quite enjoy the Scopa game in Anacapri: The Dream, and Whack-A-Rat from Sam and Max Hit the Road.
6. Yes, I think it is a great platform for adventure games. I've played Zack and Wiki (well at least up to the second to last level). It really utilizes the Wii-Mote in ingenious ways. I find it a lot of fun. There are already adventure game companies planning on porting games to the Wii. For instance, Telltale Games has Sam and Max and the Strong Bad game coming. I would hope that more adventure game companies will catch on to the craze and bring their games to the Wii.
7. I don't have any ideas myself, but sometimes there is a downside to coming up with new ideas in that they may not always work or people may not like them. Even though I'm all for new innovative ways to enhance the adventure game experience, sometimes it's best to stick with what has worked and is popular in the past. For me, nothing compares to the classic games of the 90s.
