Your Garmin help, please

Getting a bit sick of my 520 after an ever-declining battery life and then randomly turning off a couple of times during my last ride. It doesn't seem to like recording when attached to an external battery source, which isn't a problem I can find anywhere else on the internet. And finally the tiny memory means replacing the mapping region on the SD card is tedious.

In terms of a replacement my priorities are:

• Good battery life. I'd like to be able to navigate 100 mile+ routes without having to worry about being on the nav screen, but also all-day affairs for longer tours
  
• Picks up external sensors without serious detriment to the battery
  
• Not enormous. Don't really want to strap a smartphone wannabe to my bars
  
• Simple interface and software that doesn't crumble the minute you look at it
  
• Wireless syncing: adding routes uploading rides without having to attach a cable
  
• Doesn't need to do the whole 'smart routing' thing. All I need is a breadcrumb trail that I have pre-plotted, ideally with turn guidance
  
  

Obvious candidate to me was the Element Bolt or Roam. Any others to consider?