I didn’t give up and after checking all other things I’ve finally done what I should at the very beginning. I’ve removed the “item” class name from the li tag. Instead of the code from Components Guide:
<ul class="list">
<li class="item">
...
</li>
</ul>
I started to use:
<ul class="mylist">
<li class="myitem">
...
</li>
</ul>
and you know what? My app started to be responsive again. A simple list with 500 items and slow ng-repeat is now the same speed as the forementioned Onsen list and even faster and feels better than your collection repeat solution. I think there’s something wrong with the code in ionic.js that handles lists, but I’m more than happy that I can stay with ionics 