i dont know if this was answered between page 4-7 didnt read after that ,
but multi email selection was/is available since day 1 ..
when u go to mail app > mail account > inbox
tick the inbox ( mail name ) , and select delete , a new window will pop up , so u can multy select mails for deletition .
dont know how u could miss that .

as for the app manager , yeah its slow , some time too slow , specialy when u go to check for updates etc .. when installing an app and then have to wait for the hole list to be refreshed again , but i can live with that .