It doesn't take much to make me happy, and for all you techies out there, let me know if you agree:
Slim is good.
If no physical keyboard, responsive, accurate touchscreen is a must
Tethering, can this phone do it? Through what interfaces? Ad hoc wifi/bluetooth/physical?
Any rear facing camera?
Like gm0n3y said, planned hardware specs and performance LG expects to incorporate
Beyond that, if it makes calls and can be made compatible with removable memory and either CDMA or SIM cards, then you just created the perfect phone.
Take note, cell manufacturers ; )
I know that the Android OS is capable of working with all of the above options, it's merely up to the manufacturer to facilitate all the features.