In my experience, developers who are usually focused on PC/console games tend to miss the mark on handhelds.
The main problems I have seen are; trying to port games and not modifying the difficulty/controls (Lara Croft and the Guardian of Light) and creating games that are way to involved and require a lot of time to play (Inotia series).
Most of the major development companies want to push their big name titles to the new platform without spending time on redeveloping the games to work specifically for the device. A good percentage of the market is looking for casual pick up and play titles and this is not what they are delivering.
This has left the door open for smaller independent developers to really shine. They are developing specifically for their chosen platform and it shows. Easy to learn but difficult to master. Some examples are Angry Birds, Doodle Jump, Cut the Rope, Dead Runner, Canabalt, Fruit Ninja, etc.
I'd love to see a scaled down, almost jRPG version of Sacred for mobile devices, but this would require a full rethink on the way the game plays and I definitely wouldn't want them spending development time that could be going to the PC version to make it happen.
Infinity Blade is great, really enjoying the 'bloodline' concept, great way to build on your progress. If you like the visuals of the game, grab 'Epic Citadel', it is the precursor development environment and allows you to walk around a full castle layout. Very cool stuff (free too).