A 34F/28R gives you a low gear ratio of 1.21, your current low gear is a ratio of 1.39 so it will be easier. But if you pedal when going fast down hill you might not like what the 50/11 combo feels like.
Changing cassettes to a 11-32 might give you acceptable results with a low gear ratio of 1.22 and preserving your current high gear. Of course there will be some shifts that will have more change in ratio. However depending on you, it might be a non-issue.
You will need to check if your rear DR can handle that big a cog. My 105 5800 can. Cassettes aren't that expensive and are easy to change. Depending on your crank, chain-rings can be inexpensive or some require a new crank entirely.