1. Crusader- The two Crusader games, No Remorse and No Regret, are some of my all time favorite action games. For starters, your character, The Silencer- is one of the most complete bad-asses you'll ever play. Second, this series would benefit wonderfully from modern tech and gameplay mechanics. The Silencer incorporated cover-based gameplay years before Gears of War made it popular, and I think it's time this classic returns. Viva la resistance!
2. Alone in the Dark -2008's Alone in the Dark was a mess. And that's being extremely kind. With the exception of the PS3 version which had a little more time to cook, it was almost unplayable. In any case, since 2000's New Nightmare, the series has derailed considerably from its moody, Lovecraftian source material and become...I don't know what. A sad fate to befall the progenitor of the survival horror genre, and I don't think the series deserves that. The solution? Ditch the CSI/X-Files crap and go back to creepy, mysterious settings- preferably in the 1930s like the original trilogy. Actually have the player be...Alone...in the dark!
3. MediEvil - MediEvil was an awesome game for the original Playstation. And what thanks did it get? One measly sequel and a PSP remake. The re-animated skeleton Sir Daniel Fortesque should be one of Sony's most important characters, but it seems he's been left by the wayside. I think it's about time he joins Nathan Drake and Kratos in Sony's Hall of PS3 Heroes.
4. Rocket Knight Adventures - What might at first seem a takeoff on the Sonic the Hedgehog style mascots with attitude, the Sparkster games were a unique pair of very enjoyable platformers. Konami is one of my favorite developers, and this game is a great example of why- they make games that come together really well, and are extremely fun to play. I'd rather see them give us a new Sparkster title than see another Metal Gear.
5. Star Wars: Dark Forces/Jedi Knight - Somehow lost in the mix of high quality shooters and low quality games based on the Star Wars prequels, the exploits of mercenary/Jedi Kyle Katarn may be gone, but they're not forgotten, as Katarn has become one of the more popular expanded universe Star Wars characters. Unfortunately, we haven't seen him in a new game in ages. And we'd like to.