I'll give you my feedback (I'm not very good at games mind you)
1. Err OK. Not sure why you wanted to do that and there are plenty of places you will die if you are under-leveled. You can easily get to the final fight at level 2 if you want. And then they will kill you. The crocs will most likely kill you first if you just wander in and hope for the best. For sure some fights are difficult for where they are (the frogs for example) but you can always ignore them and come back.
2. The only min:max character you can pick up is Sebille (and only if you don't care about her having a points in Lucky Charm and Arrow Recovery which are both pointless). Red Price makes a good mage, Louise you need for a couple of dialogue options. I've found no reason to pick up Ikea-Ben-Ali although I do like playing rouges.
3. I'm not sure about that. The inventory system needs work but whether keys should be combined or vanish after use I don't know. Removing blank space would be good enough for me.
4. Making repairs even more tiresome is a terrible idea. It adds no value to the game except adding a bit of timewasting and irritation. I for one do not enjoy wandering off for 20 minutes to get someone to repair something or perhaps buy a hammer off them. It is rubbish system and should be dropped as in the most part items become useless when you level up anyway.
5. Levitate still exists. It is a scoundrel skill you can buy or if you an elf you can eat someones head as soon as you get into the marshes to get it. I don't find it particularly useful - items that give immunity to stun/charm/freeze are more helpful. It was useful in the first DOS as you could run over lava surfaces to avoid things. In this game, not yet.
