The appealing thing about WP7 is its XBOX LIVE, Zune, and Windows integration. Which is great if you use those services. The only problem with the LIVE integration I've seen so far is it doesn't seem that interesting in terms of games and offerings. I was hoping more to play XBOX LIVE Arcade games on the phone. Or do what Nintendo has done before where you can play a pared down or minigame on their devices that connects back to your account (Pokewalker and Pokemon for example).

For example, I believe Fable had a augmented reality game that could benefits your in game character in terms of money. WP7 needs more games that mix the two worlds together. And as a bonus it can benefit both the XBOX 360 and WP7 in terms of hardware and software sales.

Offer ways to earn EXP and money via the phone in games. There are a ton of games that use EXP or money to unlock equipment. COD for example for gun or perk unlocks, Halo Reach for visual armor, etc..

And there are far more innovative ideas such as allowing a second player to use the phone to affect your in-game world. Integrate it with LIVE so you can affect your online friends' world when your away from your own XBOX.