This is turning into an Ecoboost advertisement ...
and with good reason, I might ad.
The 5.0 would tow that trailer just fine. But there will be lots of shifting, higher rpms in all situations, and it will just feel like it's working harder overall.
The EB would cruise along in 6th gear under nearly all highway/freeway situations, resist downshifting and will tow it perceptibly easier.
Like I said, the 5.0 should do just fine. It is more about what kind of towing experience you are looking for. I know that for me, the EB is a no-brainer when considering 1/2 ton options. I love mine.
2008 Hornet Hideout 27B
2010 Chevy Suburban 1500 LT, Z71 package, 5.3/6A/3.42
2015 Ford F150 XLT Supercrew, 2.7 Ecoboost/6A/3.55 LS
Prior TVs:
2011 Ford F150 Ecoboost 3.5
2006 Chevy Silverado 2500HD Duramax LBZ
2005 Chevy Suburban 1500 4x4 LT, 5.3/4A/4.10