Here's my pet-peeves about LBP3 which aren't necessarily problems but are things that annoy me:

1) In community levels, bringing up the Level Details while you're inside the level no longer shows the number of plays, likes, or hearts.
2) Navigating up in menus such as the level details menu of a community level switches the focus to the level author's name instead of scrolling up in the menu. (I think this happens on profiles, too)
3) Recent activity is misleading. For example, if you commented on a profile, the person you commented on will appear to have commented what you did in your recent history, because their name appears along with your comment after it (no indication that it was yours) and you'd actually have to see the details of the event to see that you left the comment.
4) The Paint tool is annoying. There should be a setting for speed because the brush goes way to slow for me, the color selection and brush selection menus are annoying for controllers. (not sure about PSMove Controllers) They're very tedious to navigate, too, and you usually have to select the color or brush you want multiple times because it doesn't register the first time you've selected it.
5) There's no way for you to import your own picture into the Paint tool, so you can't really create custom stickers with transparent backgrounds which I was hoping that there'd be an option for in LBP3.
6) There's still no Dislike option, and LBP1's star rating system was better than the Like/Dislike system in the first place.
7) The comments section has been moved on community profiles, which is confusing.
8) The pins don't show up immediately when you're on someone's Earth.
9) The screen lags when you enter community or story levels.
10) When you enter an adventure map and press the back button quickly, you'll leave the map and the adventure map badge's appearance will look as if it was in the process of opening.
11) The cursor in create mode is annoying because if you're trying to select something in the foreground and there's stuff in the background, it automatically switches to the background objects and messes up the camera. There should be a system where you can choose which layer your cursor is in (like how you can change the layer of objects with L1 and R1) and maybe be able to automatically select objects only in the layers near the cursor's layer (like LBP2).
12) I don't really like the new single sound object layout because it gets confusing with a bunch of sound objects that look exactly the same if you're creating some complex logic.
13) Only default LBP1 backgrounds and a few random settings are listed as background noise options. None of the LBP2 or DLC backgrounds are usable for background sounds. For example, if I wanted my level to sound like the DC Comics Pack background but I didn't want the background itself, that isn't possible.
14) This is more of a suggestion, but I've always wished for an option to import in video and audio files into LBP as music, videos, etc.
15) The level trailer feature kind of blows. There should be options to add music, text, video effects, etc to level trailers.

And lots and lots and lots more -.-
- Wave Generator has errors when using speed scale.
- Signals can no longer be greater than 1.0, very foolish of Sumo to take away that feature.
- Cursor goes crazy when zooming in and using corner editor.
- The hook hat lags awfully much.
- Finding levels to play is so mush harder in LBP3.
- You can't adjust the size of the screen.

They better fix these issues or this game is unplayable.

Yeah, and how the hook hat takes off your costume!

And the slice and dice tool glitches and sometimes doesn't allow you to use it in places that you should be able to.