What you want is fee-shifting. Doesn't need to be tied to the presence of a motion to dismiss. Unfortunately this is so un-American a concept we literally call it the French Rule (or the English Rule)[0].

The purpose of a motion to dismiss is to make getting rid of bullshit lawsuits easier. That is, if someone sues you for something that, say, isn't actually illegal, you get to throw out the lawsuit without having to go through discovery and a trial. This is important because rich people who can afford lawyers will absolutely sue[1] you as a censorship tactic, and being able to dismiss the suit quickly is the difference between a $10k legal bill and a $100k legal bill. In fact, anti-SLAPP bills work by giving you a fancy motion to dismiss that also triggers fee-shifting - which is enough for the rich person's lawyers to dissuade them from a censorious lawsuit.

So I don't think we should make motions to dismiss more perilous to file. They're the last speck of respectability in our awful legal system. We should instead make wasting the other party's time cost money.

[0] Except in copyright where you can get fee-shifting under specific conditions.

[1] Strategic Lawsuit Against Public Participation, or SLAPP