Don't you think it's about time to start communicating that you;
- acknowledge the fact that the IOS iphone app is not performing as expected
- inform what your plans are to fix this (what, how and when)
For me it would work if the old version would be available, that worked very well (fast, responsive, doing what an Iphone app should do).
I am a very heavy user (MacBookPro, WindowsPC and Iphone), the moments you use the Iphone app is when you want to;
- quickly check a note
- quickly add a new note (in order to enhance / complete it on the laptop/PC later on)
- quickly change some minor things when you are on the move (reminder date, small remark etc.)
The way the current app is performing stops me doing just that :-(
Please be aware that most of the Evernote users are organized and structured people who have tried quite some solutions out there.
The reason why I (and I think most users) did not switch is that Evernote is a super tool as it's working on IOS, Windows, mobile devices and and on a functional level well thought through.
..... take these loyal users on board and communicate your plans to them..... don't make them run away, that would be a pity.