Perhaps this an American interpretation, but "if you have a better idea, I'd like to hear it" sounds confrontational.
"I'd like to hear it" can be used to express you don't believe there is such a thing.
If you can come up with a single positive thing to say about that creep, I'd like to hear it!
If you have a good reason this lamp is broken, I'd like to hear it!
If you have a better idea, I'd like to hear it! No? I didn't think so.
If you have a better idea, I'd welcome your input.
I'd appreciate hearing any better ideas you may have.
Please let me know if you have a better way to resolve this.