That is a very good point! Right now we up it to 1024mb on low-RAM machines here. We could certainly experiment with increasing that to 1500 or 2000 and see if it helps.
If you have the time/inclination to try it out yourself, you could configure it by adding a new variable to the env: section of your app.yml file:
Edit: 
this is now the Discourse default. No need to configure yourself
NODE_OPTIONS: "--max-old-space-size=2048"