Like you mentioned the server behaviors can sometimes cause the page to function slowly when you are editing it if there are a lot of them on the page or if they are complex queries taking place.
Do you have a template applied to the page? If so try making a copy of the page and detaching the template to see it that helps with things. You can also try making some edits with some of the panels closed, like the application or files panel and maybe the property inspector. Also having lots of Spry objects on a page can cause it to have delays when loading and editing.
Since the other DataAssist pages are not having this problem it seems like it may be something to do with the functionality on this page. Please post back with this info and if you do not get any further I will open up a ticket for you so we can look at the files and help you work this out.
