WoW, Rift, Guild Wars, SC, competitive FPS's, Witcher style RPG's, Elder Scrolls, etc. these are not games you will be playing on a tablet. There exists a clear divide between casual and serious gamers.
I don't mean to imply that there's anything wrong or inherently inferior about the more casual side of things, just that they really are two very different markets.
Then there are the hardcore games. Eve Online, World of Warcraft, Call of Duty, Grand Theft Auto, Street Fighter 4, etc. These games often require lots of skill or dedication, and are often big budget titles.
But there is a ton of stuff in between. Games that you might be able to play fast but are very difficult (like Spelunky), that the player can choose how to play (Minecraft or Terraria), that just aren't designed to be highly competitive and difficult (Sly Cooper series, maybe Ratchet and Clank series), aren't hardcore ultra-deep sims (SimCity, Game Dev Story), and many sports games (Madden, NBA2k, etc).
Some people go really deep on some games and play them in a 'hardcore' way. The lines aren't easy as I know many people think World of Warcraft has been dumbed-down throughout the expansions to where it may not be 'hardcore' for many people.
But that's my general taxonomy. Casual, 'normal', hardcore.
Could you explain that? I've played some pretty great games on my iPhone/iPad over the last few years. There certainly are games that could stand up to the average PC release (remember BattleField 7 and Call of Duty 18 are not average). Many are at least easily comparable to games of the 16 bit era.
A sample from my purchased apps list: Battleheart, Beat Sneak Bandit, Brainsss, Device 6, Fieldrunners, Edge, Game Dev Story, Girls Like Robots, One Tap Hero, Punch Quest, The Room, Slayin, Spider, Spy Mouse, Star Command, Supermagical, Tiny Heroes, Tiny Thief, Waking Marks, and Zenbound.
This doesn't include 'tiny' games, ports, digital version of boardgames, etc.