I don't mind saying, this generation has simultaneously been the longest and, overall, hasn't really provided all that many "what a piece of shit moments". Which is impressive, considering.
Downloadable demo's from online sources (PSN/XBL) has definitely helped minimise my curiosity getting the better of me (re: RE6, DmC etc).
I'd say my list was more about disappointments/letdowns > outright worst games ever, last generation:
Burnout Paradise - just wasn't what I at all wanted off the back of 1-5 for PS2 etc
SSF2HDRemix - just looked unbelievably, desperately ugly
Lost Planet 2 - Again, not at all what I wanted vs the original, which was great
Resident Evil 5 - not horrendous, but not a patch on RE4 before it.
Ace Combat: Assault Horizon - Horrible, arcadey shite
KOFXII - no explanation req'd
Need for Speed Rivals (PS3) - one of those last gen, piece of shit ports. Played PS4 version since and it's 100x better.
MotorStorm: Apocalypse - Hurts to mention this, as the first two outings are my fave racers of the last gen, but the 3rd instance was, should we say, not on target
Blaz Blue series - expected more than just GG Alternate universe. Oh well. More of the same it is then
Armored Core sequels - PS1 & PS2 titles were great. Not sure what happened with the next gen versions, but they were convoluted and dull
Test Drive Unlimited 2 - after the first one was so great and well realised, not sure how they could fuck this up so badly
Street Fighter X Tekken - Should have been amazing. Really wasn't.
Silent Hill Homecoming & Downpour - I didn't even bother tbh.
Red Faction - loved the original two. Not sure why the change to TPS was deemed 'necessary'
Soul Calibur IV - felt stiff and boring vs the first 3 on PS2. Also, having SW characters in there was a real turn-off/no-no for me.
MKvsDC - a typical Midway 3D fighter. Massive leaps have been made since via MK9, which is actually good. Not MKvsDC though.
Resistance 1 & 2: These were just crap. I will say though, R3, though too little - too late, was actually good.
Twisted Metal - lacked all the charm and 'qualities' of the originals on PS1. Should never have (bothered) been made
Alien vs Predator - Dull/Generic
Crysis (PS3) - I never had a PC to play this bitd. Expected great things, but this was just as average as they come. Disappointing.
Soldner X - Dull as dishwater Euroshmup (Soldner X2 was good though!)
(Any) Virtua Tennis after VT & VT2 for DC - they just don't have that magic and suffer from generic disease
Bodycount - loved Black (last gen), but this unofficial sequel was just bland as fuck
Ridge Racer: Unbounded - some shitty cash in using RR's legendary name. Avoid.
Bionic Commando (Reboot) - Dull/Embarrassing
TMNT ReShelled - Wank