1-4: I personally didn't notice an overly long tutorial, but I also may have rushed past it having played earlier versions of the game and being very used to how this type of game works.
That all depends on the game, and honestly this doesn't differ that much from a fair number of RPG games that have been made already, so it may be a bit of the "use wasd to walk and mouse to aim" incredibly basic tutorial stuff that an FPS might have, where the tutorial assumes you've never played a game before.
I feel like anyone with at least a little bit of knowledge of how a lot of JRPs work shouldn't have much issue with this game, tired or not. Even then, I feel like it's just differing opinions on how tutorials should be handled. Some things should allow you to learn one thing at a time, but that's not always needed.
5: So, the tutorial fight that you're (theoretically) not supposed to lose doesn't end if you just guard... Going along with point 6, she's supposed to be a soldier / mercenary at this point, and not corrupted. She's fighting bandits that want to kill / capture / rape her, why wouldn't she fight to kill instead of just standing there blocking.
6: It's the style of game and is (as you noted) relatively early in development. Not all the assets are done, including not having the still clothed versions of the cut-ins for the various actions, and a lot of cut-ins are still not in the game at all.
The slow corruption is still very much there, requiring multiple rounds of hitting the max level (IIRC it's corruption in game) of a given body part before enemies can do more advanced things (talking, then touching, then kissing/ licking, the dicks getting involved.) It also takes a fairly long while before you can have Saria herself initiate anything, unless you get lucky focusing specifically on getting there.
7: Again, early on she's not corrupted and is dealing with bandits, monstrous creatures, or animals. Killing early on makes perfect sense and not everything needs to be erotic / porn.
This game has frequently been compared with Karryn's Prison, in terms of it's general game play style. Maybe you could try that one (if you haven't already) to see a "more complete" version of the systems this game will likely have later on.