1 - Inflation can be a problem when there aren't enough users on the platform or enough ways to use the currency. It isn't necessarily the main problem. There are ways to get around the inflationary aspects of Steem. One of them is the ability to hold Steem Dollars. As long as the SD can hold the peg, you still get a fairly close 1:1 exchange when selling. If Steem is $0.01, then you'll get 100 Steem per SD. If Steem is $0.50, then you'll get 2 Steem per SD. If you're holding SD, then it doesn't matter if the price of Steem fluctuates.
The main concern about the inflation is the dilution of Steem Power. To help offset this, they pay interest on your holdings that is equivalent to the inflation of Steem. Theoretically, you can use those interest payments to purchase Steem at it's current price and power it up to maintain your stake. Whether that's actually proving to be true is the question. But with the relatively rapid decline in Steem price, you'd have to be buying and powering up quite often to maintain your share, or receiving relatively large curation rewards. I think this is one of the main problems for attracting investors.
2 - The distribution is all wrong, but I don't know what can be done about it now. There is definitely some concern with how it's playing out. The largest stakeholders are earning large amounts of Steem and SP from their roles as witnesses and from their curating, so they can essentially power down and cash out without losing any stake. This is part of the pressure being put on the exchanges - consistent, large sell orders from a handful of stakeholders. It would be better, in my opinion, to try to sell them on an internal market - or even encourage them to use the Steem on actual products (from places like Peerhub) - rather than dump them on the exchanges. However, this is probably not going to stop because there doesn't appear to be any incentive for them to stop selling.
3 - This may be something that we will eventually see. I don't know if there's any way around it. As a "decentralized" platform, if the largest stakeholders of "Steemit Inc." eventually do turn things over to the community, there will surely be users who would be willing to sell some ad space on their blog and posts. As users ourselves, we will decide on whether or not we want to support those users and their advertisers. I don't think it's necessarily a good or bad thing. It's just how things will evolve. If it's needed for Steemit to survive, then it will probably happen. It may happen even if it's not needed.
That's half of the excitement, isn't it? Not knowing if we'll be hit with ads every time we click on something? I sure hope they get that development on track.