If only this was a simple question. But with old being passed of as new, and innovation being retracted to appease the whiners, action rpg's having the rpg knocked out of them because the fps crowd winge that rpg's aren't fps enough for them, with competition between the major companies leading to hard to work with architecture, crippling unreliability, or cloning of features, companies pushing a peripheral device so hard that great IP's get ruined to accommodate them, or become unusable with out these peripherals, with gamers' records of completion being incomplete unless they buy the new piece of tat, and then there's uninformed consumers enabling it all by parting with their cash to acquire whatever they are told to, whether it be advertising from the big companies, or little Johnny/Jenny telling Mum, Dad, or Gran that they have to have the latest CoD/Batlefield, & that age ratings mean nothing, or the latest Fifa/NBA/NFL#(insert next year's number for the same game all over again), what remains is a mess in which there is very little genuine 'New', not from the Hardware, or Software, or game concept, and what is new is hard to see amongst the fakery, or quickly gets put to an end, or corrupted.
With an awareness of what goes on in the industry in mind, the next most important consideration when defining what is good for games is the question 'Good for who?' Devs? Publishers? Hardware manufacturers? Critics? Consumers? Casual Gamers? Hardcore Gamers? Units sold? The industry's survival? The Industry's growth? Or the actual quality of the product? Although it is hard to get agreement on what is a quality product beyond freedom from bugs and glitches, my money would have to go squarely with the quality of the product.
So where is the new? How have games changed over the last #of years? The biggest change has to be the growth in online multiplayer for consoles, resolutions, frame rates, DLC, & DRM. The second & third will always happen as long as hardware can crunch numbers faster. DLC(Downloaded Content) could have been a great way to extend the life or replayability of a game, but has 90% of the time become a cynical money grab in return for substandard tat or a compulsion to buy to in order to still possess a complete product. DRM may not be such a new idea. We all know about code books & Lenslock etc. But all things were new sometime, and DRM seems to have exploded over the last 15 years. Personally I find it hard to link DRM to quality of product from the users point of view. More meaningful changes affect gameplay itself.
Mass Effect 1.
Bioware (Pre-EA) Wanted to create a single player RPG on an Epic Scale across 3 games, with mini games that just relied on following a sequence rather than problem solving ability or a level of skill, moral dilemmas, & decisions that had long reaching implications in #1 and into & through it's sequels. For those of us that loved Mass Effect for the games philosophy and it's potential throughout the series. This philosophy was seen as a good thing for the future of games.
Mass Effect 2.
Bioware (EA-owned) Big changes happened here. The Cerberus Network was introduced as an incentive for buying a brand new copy of the game instead of pre-owned, delivering a number of DLC extras for gratis, or a Network pass could be bought separately for those acquiring their disc preowned. This was seen by most as a good move as it took nothing away from the main game. it worked for the Devs and Publishers without upsetting the consumers. Encouragement to buy new was a preferred new approach to the pre-owned industry. Shame is it was never repeated, & became the thin end of a much more insidious wedge.
Changes to gameplay were large also. Basically the appeasers gave in to the (Non-RPG) whiners and the Action RPG Became a shooter with lots of talking in it. Basically from the RPG players standpoint EA saw a bigger profit in selling out to the FPS players. Some basic premises of the ME universe were removed and replaced with some complete excuses. The mini games did though improve. The first of those between games implications were mostly disappointing as they were pretty blunt and obvious. A mixed bag of changes, but the gameplay ones for me were a negative.
Max Payne.
Going a long way back now to the game that first employed 'Bullet Time' Strong narrative via voice over, but the Bullet time was the new & positive contribution. It has been imatated in many forms since from slow time in sniping games to Tequila time in Stranglehold.
Too Human.
Silicon Knights tried to introduce an alternative to button mashing for this much maligned title. Imo the wolves had every intention of slating this game before it even came out. Dennis Dyack famously exploded at the Critics, and rightly so for what I observed. None of them tried to work with the new control system, instead just seeing an opportunity to make a name for themselves with endless unfounded criticism. The game had its faults like the tediously long, unskippable Valkyrie animation at every death. But the new control system was killed off by the critics before it could get out of the gates. For someone that is fatigued with standard button mashing I loved the direction that Silicon Knights took and think that the games industry has harmed itself by rejecting this fresh thinking.
Mirror's Edge.
Another much maligned game that had it's faults, but none of them were what was being levelled at it. It was a pleasure to play, challenging in just the right amounts, and the free running felt awesome. When you found your flow, you could really feel the 'Flow' Many other games have free running elements to them, and it is often compared to the likes of Assassin's Creed, but none of them had free running so distilled that it became the game. Those that complain the loudest often appear to be the one that fall down a lot, through lack of skill, coordination, or timing. I hope to see this level of free running make a return.
Rhythm games.
DDR, Guitar Hero, Rockband, DJ Hero, Band Hero, yadda yadda yadda. The genre itself was a good move in gaming. The introdution of instrument shaped controllers was a good move although reliability was an early problem. I love being able make some seriously kickin' tunes come out of my console, so when this was new it was definately good for games. Unfortunately when it wasn't so new it got over-saturated and drowned in it's own, mostly Activision, cesspool.
Rocksmith.
A Music game rather than a rhythm game. It took the next step and actually uses your own real electric guitar. It teaches you to play guitar from tuning, to one or two strings all the way up to what ever you can handle. Unfortunately the uptake of this title wasn't very high, and in Europe it's release was by a whole year over legal issues. But the game's use of a real instrument instead of a controller or halfway house is definately a good innovation for games & music.
I was also going to touch on the following but I have a family to look after and this is taking up quite a bit of time:
WiiMote.
WiiFit.
Playstation Move.
Kinect.
Wii Music.
Online Multiplayer.
DLC.
But generally I say when it's good for games, that's when Publishers and Critics kill it off. When it's cheap tat that doesn't live up to it's claims, that's when they bring on the hard sell.