For me, the only concern is reducing incentives to hold SP from the perspective of investors, since curation reward is now a way to to earn profits (which is totally wrongly aligned with the original goal of "curation"). Inactive reward can be one more option, or we can increase SP rewards.

The incentives to hold SP will not be reduced because eliminating curation rewards will make the platform a lot more valuable, it will improve power concentration a lot and would make it a lot more appealing for business to integrate because of this very reason. You say curation rewards is a way to make profit, can you tell me one single investors who earned profit from curation reward? There are none because the value of steem has only gone down.

Inactive reward can be one more option, or we can increase SP rewards.

I think that inflation can be used to incentivize people to buy steem, I actually created a post about it.
So yeah I think using a portion of the reward pool to distribute to stake holder is a good idea and I also liked the idea of only rewarding inactive users.
I think steem power should be removed entirely, many in the community agree with this. It would be a lot less confusing for newbies to have 2 currencies instead of 3. Basically your voting power would be the steem in your wallet and users would be able to vote with steem that is at least 7 days old to prevent double voting.