Hello,
Touch screen is not an issue, its pretty good for use. Its the flip models where you can rotate your screen to the back of the laptop to use it as tablet. Lenovo Yago 2 Pro was good one, but Dell's implementation is not good. Ghost touch means, you touch on the center of the screen, but there's more touch events happening somewhere else too auto-magically. Making unintentional opening / closing apps.
Battery for my XPS is going good 56% wear level after 2 years, I bought mine March-2014. Gives me about 2hrs now, was 5hrs when new. To get better battery life you need to learn some tricks. There are 1000 charge cycles in most of these batteries, and 1 year have 365 days. If you cycle your batteries correctly, you get about 2.5+ years on one battery.
SSD are super duper fast drives, it will boot your laptop in 10-15 seconds, apps will open like notepad. Plus it won't damage easily when you carry your laptop around while its on, because there's no spinning components in them. It's all like USB flash disk, but faster. Usual life is 4-5 years.
I would recommend having a regular external HDD and make File History (Win7+ feature) backups of your important work on it weekly. SSDs once gone bad are hard to recover data from. Even if you do shift-delete some files, and run undelete tool, you'll get corrupted file back, because data is handled differently than old HDDs.
Metal body is not necessary if going for 13" model. Small builds are sturdy. Just pick it up from one side and notice if there's any flex feeling to it, if not its good build. 4th Gen or later i5 is best for performance and battery.
Glad to help from my experience 
