Fight! Fight! Fight! lol.
The waldstien isnt easy to read or play, all Cmajor (3rd movement moves to Eb but mostly it is C) so you have to notice all these stupid accidentals. Form/Memory is hardest to crack in Cmajor as well in my opinion. I guess you could underestimate Waldstien because patterns look logical and simple, but put the foot down play it at peformance speed and then you'll see its hidden difficulties and how tough it can be to position yourself constantly.
Op111 isnt too hard actually. There is a lot of repeated pattern which makes absorbing it very fast in many sections.
Listen to more of Beethovens later works. Like piano sonata, op101,109,110,111, and string quartets op127,130,131,132 and 135. In these Beethoven abandoned the classical 3 or 4 movement structure. Like the 111 only has 2 movements, there is much more emphasis on the constrast between movements. So i guess chosing pieces which hold the same idea would echo what Beethoven was trying to do.
Beethoven sorta lent towards variation and fugal procedures in his later works and the themes where more gradually presented. In this case lots of Bach pieces come into mind which echo similarity.
His "middle period" style found its way again however in the Hammerklavier Sonata, op106 and the Ninth (Choral) Symphony. But these works are colored by a new ideas and directions, just listen to them to hear for yourself.