This project could be really interesting - especially the way that rather than "starting again" like most altcoins, it works by "transferring" existing bitcoins onto a new, more feature-rich chain. A couple of things I would like to ask/points I would like to make however:
1. What marketing/incentivisation are you planning to ensure a plentiful userbase?
I appreciate you are still in the development stage atm, but do you have any solid plans about this yet that would give potential investors confidence?
2. Is the domain name registration really any different to Namecoin? And is having a competing system really a good idea?
Your sole grievance with NMC appears to be that it is not AUTOMATICALLY browser-integrated. But your solution seems to amount to no more than installing some sort of browser plug-in alongside the client - I fail to see how this is not (trivially) possible with Namecoin? Anyone could just make an installer package that includes a .bit DNS resolver plug-in as well as namecoind/Namecoin-QT client. Also, your "no transfer" of domain names between addresses probably wouldn't work in practice, because people would simply sell the private keys for the addresses themselves.
Additionally, though I appreciate yours is only the second such system, is directly competing (at the moment) against Namecoin really a good idea? Namecoin right now is massively underdeveloped and underused, and offering an alternative at this stage could not only split developers and users between the projects, but would also decrease the value of NMC (because if R160K.bit was already taken, you could just buy R160K.nxt) and thus lessen interest. Although I feel competition is a good thing for crypto-development, I think it would be best to try and get Namecoin realising its full potential to get a feel for what's possible with decentralised DNS before competing away its users and developers. After all, DNS is different than coins: an altcoin directly competes AGAINST bitcoin as a potential store of value; but two DNS systems can complement each other: it is not a strict either/or whether to buy R160K.bit or R160K.nxt, you could have both if you wished; therefore, waiting for Namecoin to come along much further will not necessarily reduce the likelihood of people using NXT for domain names if it's implemented the future.
3. Will the file storage only be for "official" files (like the client), or will anyone be able to upload files?
I like the notion of storing the client on the blockchain - although this of course will only be the official client, and will not include any third-party clients. Also, if file storage ON THE BLOCKCHAIN is available to everyone, even if it is expensive, then the potential for blockchain bloat is enormous (also it will preclude the possibility of implementing some sort of mini-blockchain system). There is
possibly an alternative - an idea I came up with a few days ago, though only managed to work out a couple of features (it may yet be impossible). (
https://bitcointalksearch.org/topic/swarmcoin-possible-new-cryptocurrency-with-decentralised-cloud-storage-326808). The basic idea is that peers contribute storage space (measured in gibibytehours) and are rewarded for it in coins (could be a "coloured" altcoin on the NXT chain) which they can then either use to pay for file storage or can sell via exchanges to other users who want to buy storage. How the reward system should work, or the paying-for-storage, I have yet to devise; but I have already found a way to link uploaded files to coin addresses. I should warn you though, that idea is very rough (and possibly impossible) to implement.
4. What protocol improvements (over bitcoin) are you considering implementing?
You've already mentioned faster transaction times, PoS over PoW, and some new types of contracts; I think you also mentioned somewhere about coloured coins (or equivalent). But what about things like "mini-blockchain" (or one of the equivalent proposals like CoinWitness)? (Though in fairness that is perhaps best done on a client-level: users decide how much of the blockchain they want to validate and store locally, and the rest they get from their peers). What about "ZeroCoin" (although the current proposal is quite impractical due to validation times etc.)? What about "micro-payment channels"?