There are a lot of fantastic flight sims out there that have terrible UIs, engines (API support) and controller support. I would love to see things like Jane's AH64-D Longbow, Longbow 2, F-15, F/A-18 games updated, for example.
Unfortunately space sims have also gone the way of the dodo.. The original Lucasarts X-Wing and TIE Fighter games in a modern engine would also be amazing. Even though I love the FSCP it is more of a hack to me than a real remaster, so an updated Interplay Freespace 1/2 would also be great.
The same goes for some of the best racing games from Crammond and Papyrus featuring the best physics engines and best seasons of their genres: Grand Prix 2, Grand Prix 4, Grand Prix Legends.
I also miss the immediate accessability but adequate sophistication and incredible fun of some early strategy games such as the Microprose/Maxis stuff: Civilization II, Sim City 2000, Transport Tycoon, Theme Park, Railroad Tycoon II, Sim Earth etc.
Some genres have somehow gone extinct and they used to be incredible fun, I don't see why they are not revived as simple indie games; topdown racing games like Super Cars 2, Skidmarks etc. for example, where are they now?
I really miss some of the old text/graphics adventure hybrids such as The Guild of Thieves and Wonderland from Magnetic Scrolls, I wonder why nobody does games like these anymore.. Not fit for the millenail generation?
These are off the top of my mind..
Retronautics: A digital gallery of my retro computers, hardware and projects.