I think Black Fly is a very good choice. On the easier side of the grade, and well protected.

Modern Times is a good 5.5

You mean 5.5+.

or 5.5d

I agree about Tripple Bulges

Finger locks to triple bulges is the best 5.5 in the trapps. Lots of continuous climbing at or near the grade.

Finger locks to triple bulges is a great recommendation.
Black Fly is short and well protected.
No Picnic used to be 5.4 so its easy but the gear below the roof is fiddly and the easy slab below is runout.
RMC is a gimme at the grade. It has one 5.5 move. The gear for the move is not the best but everything else is 5.4 or less.
Jackie is classic at the grade and well protected but not easy for the grade.
Arch is easy but scary. Physical crux is off the ground. You will know the mental crux when you get there.
Dennis is great. The 5.5 crux is off the ground and if you blow it at the crux you will be fine with a good belay. Trust me on that one.
If you are swapping pitches with a stronger leader the second pitches of balrog or alley oop are awesome 5.5 faces.
I thought the second half of the first pitch of red pillar was run out.
Middle earth is fucking hard for the grade. It was too easy for a 5.7 but .5? Really?

That's because Middle Earth is a 5.6

Too hard for a 5 too easy for a 7. 6 it is!

Across the many editions of DW's guidebooks, Middle Earth has been rated 5.5, 5.6, and 5.7-. So take your pick.