Manipulating bug tasks via the HTML UI is slow (vs. JS)

When a bug has many (≥ N) tasks (? is this the criterion?), clicking on the 'pencil' icon to edit them redirects you to a separate page rather than popping up a JS interface. It's much slower to edit bugs this way because of the page load and having to mentally parse a new interface, save it explicitly and return back to the original bug.

This often happens once you target a bug to a series and the number of tasks is increased above N - by the number of distro packages the bug affects. Targetting and subsequently bulk editing for me is quite a common operation - in the desktop team this is how we track bugs we have committed to fix - and it'd make my life better if this could be a fast operation.

I'm wondering if you could consider if it's possible to improve this flow somehow. I don't know the rationale for having a threshold here, but if that no longer stands then simply increasing or removing it would work for me. Otherwise investigate ways to make the transition to another page faster.