Off the top of my head I can definitely say:
Never B Peace - the beat is totally wrong for this song and the outlawz ruin the song the rest of the way. pure garbage. unlistenable.
Fame - i don't care that the og is unleaked, the outlawz once again completely ruin what was probably a great song. pac's verse and the hook are great but the outlawz verses keep me from listening to this song more than maybe once every 3 months. what a waste of a good song.
This Life I Lead - what exactly makes sense about taking off gonzoe, daz, kurupt, and nuttso, replacing them with the outlawz, replacing a hot-as-fuck daz produced westcoast beat with another run of the mill johnny j ho-hum beat, and calling it official? can't think of anything? that's because it's the perfect example of what NOT to do. garbage.
One Day at a Time - this is one of the few decent eminem produced beats but unfortunately for him and the outlawz, they seemed to have missed the point of the song altogether being that when 2pac and Spice 1 laid this track, with their verses they were speaking for black people, not rappers in general. So with eminem and the outlawz speaking on rappers in general they sort of throw off the whole vibe of what the song is supposed to be about and make it mad uneven as a result. the og over this remix any day of the week.
All Out/Hell 4 a Hustla - both listed here for the same reasons. First off, both og's had real gritty, grimey, and raw beats that fit the vibe of those songs perfectly. They replaced those with some techno-popish beats that not only serve no justice to the songs, but make them come off as sounding like a cobbled mess of just noise, and not a song. secondly, the outlawz re-did their verses for the remixes and this was a mistake as they came harder on the og's. thirdly, they removed a layer of pac's vocals, which is something that shouldn't be done to any of his songs as he recorded multiple layers for a REASON. messing with pac vocals is a no-no or at least it should be. finally, they removed pac's outro from BOTH songs which was wrong to do. pac was very angry on both outros, lacing both full of disses toward bad boy, jay-z, and mobb deep. i've heard that these songs were recorded during the same studio session (which, coincidentally, was reported to be his final studio session) which would explain why both sound similar in tone. removing these outros was a bad move. og's kill the retail versions of both these songs.
when thugz cry - they took off pac's chorus, completely changed both the beat and background vocals for the worst, and again omitted pac's outro. the og is, imo, one of pacs deepest and best solo joints. definitely in my top 10 of pac solos. they completely bastardized this song with the remix. matter of fact, i haven't put myself through listening to the uteot version in so long that i about forgot what it sounds like. mission accomplished on my part.
why u turn on me/lil' homies - both for same reasons of censoring out lyrics for whatever reasons and/or censoring the outro. also, i agree that maybe the og hook for why u turn on me coulda used a lil' something more, but they did it all wrong. shouldn't have took db off the hook of lil' homies either. and if they're gonna try and re-make the beat but have it sound basically the same as the og, then why not just use the og to begin with? both garbage remixes.
there's many more i could think of, but i'm sick of typing by now.