I have no problem with low preference seating in return for single rider line, but having done mostly solo trips lately, it is a little aggravating to know with certainty that no matter whether you are fastpass or regular line, the chances you will have anything other than the end seat with the least preferable viewing angle on Soarin' and FoP are virtually non existent (although, admittedly not as big of a deal if you are lucky enough to be slotted into the middle section). Just a minor gripe to me, nothing I would hassle a cast member with or anything.
Aside from the above, as to the topic of the thread, my biggest ride design pet peeve is the trend toward screen tech in place of animatronics or other more practical effects in rides. For the purposes of this personal pet peeve, I don't include screen based attractions that are either interactive (i.e. Buzz or Toy Story Mania), grand in scale (i.e. Soarin' or FoP or even the World Showcase movies), or 3D (i.e. Star Tours, Philharmagic, Muppets). So many of us are in front of a screen all day at work, then spend hours in front of screens at home whether it's tv, phones, and/or video games, we see screens virtually everywhere we go. I love the parks for the escapism it allows (and still does a super job of)and part of that is the spectacle of seeing and experiencing things you can't see in everyday life. Screens and projections in rides like Journey into Imagination, Nemo, the Haunted Mansion's hitchhiking ghosts, and a few others just seem to be taking a lazy way out. Animatronics may be an older technology, but when do you get to see them in day to day life and when do you get to see the detailed sets the dark rides have generally had?
As for projections, it may just be my personal preference, but, while I can appreciate the tech and that it's cool to be able to project faces on animatronics (i.e. SDMT, Frozen, Haunted Mansion), I'd much prefer good old mechanical features. I know you can't do as much with classic animatronic tech, but they can do a lot more with it these days than they used to and I'd love to see more of it. For me it comes down to this, when I see a good intricate animatronic, I think "wow, that's amazing, how do they get all the moving parts to work together?" but when I see a CGI projection face, I think "oh, that's fun, but it's just a projection."