Are you willing to shorten the SP power-down period to three to seven days from current period?

No. Maybe shorter than the actual 13 weeks, but not 7 or 3 days.

Are you willing to remove down-voting policy of STEEM blockchain?

Yes, but only with similar upvote policy removal.
Both mechanisms should be transferred into communities, using their own SMT and their own pool, so you can milk yourself but not the global reward pool.

Are you willing to introduce smart contact into the STEEM block chain?

Steem is already a smart contract, isn't it?

Are you willing to introduce a paid subscription model?

Why should we introduce a subscription model?
Create your own business, on top of the blockchain, with or without a subscription.