I'll probably not invest if the coins aren't censorship resistant, meaning they can't be seized by the entity that controls them. If the stablecoins are centralized and controlled centrally, they could be easily seized by those who control them whenever they want.
I guess you prefer stablecoin to avoid situations where investors money becomes more or less valuable when it's refunded. If that's the case how do you handle a situation where a stablecoin is devalue against Bitcoin or any currency the investor sent you money from? Would you consider paying Interest or something to avoid any potential conflict?  If you use a censorship resistant coin like Bitcoin, you probably could agree with the investors that they will be paid exactly how much they contribute in Bitcoin, whether it goes up or down. This should give the investors who accept the Terms peace of mind knowing that the ICO fund will not be seized by governments that do not like ICO.

I also would want such Smart-contract Fund with feature that gradually release funds to developers based on how well they have used part of the fund released to them by the smart contract. This should happen automatically.

It is really usually refundable after the ICO because it will determine if your project is a success or not. That's a good policy actually if you're going to refund if the project is unsuccessful because there are many projects in the past that didn't refund their investors.

But on the other hand, if you have this policy, do you think that there will be more investors to come to you? there are investors that are goal-driven and if they see this policy, they're likely to stop even if you're giving the confidence to them.

If you're going to refund after people invested then that means that you're project is unlikely successful.

Why create a refundable ICO if that's what you think. Correct me if I'm wrong if that's the expectation that you're about to do.