OK, after nearly one week of testing and trying and playing around I can say, the new version seems to be more stable than the one before. Currently I'm only using omweather, weather.com database and gismeteo.ru database. No additional icon packs and animation turned off.

But still I had the issue of complete crash of hildon desktop and loss of all widgets. This happened right after switching one city from gismeteo.ru to weather.com when app tried to fetch the data. The difference is that in previous version I had no chance to get the widgets back as long as omweather widget was defined on one desktop (I'm using actman for switching between and reloading desktop layout). Now I can reload current "activity" and get all widgets back including omweather. But I don't have a clue what exactly makes omweather crash the desktop.