I can't wait for ADSB/TCAS functionality to be available on them, with the relevant hardware of course, Even a full blow MFD setup
MFD is getting close; you can already buy sensors that work with the iPad and some software that uses them.
My main gripe with them is that they all work over WiFi, which is a pain in the butt. I would hope one day they become Apple licensed "Made for iOS" and can use USB or at least Bluetooth. Nothing like a reliable wired connection for your MFD and PFD...
The problem with ADS-B is that all the affordable stuff is now made for UAT 978 use in the US only. Remember that the FAA re-broadcasts mode-C targets so if you get a UAT receiver you get traffic even for those not aircraft ADS-B out equipped. That's immediate value and they are selling like hot cakes in the US.
For our 1090ES system, it is clearly a chicken and egg problem. Even if a $1000 box existed to receive the air-to-air only broadcasts, you would still only pick up 1% of GA aircraft? Who would pay for that? In Europe the level of ADS-B adoption might be quicker and it may become feasible for manufacturers to make products we too can use, but they won't ever be as useful or good value as in the US. (Thousands of RA-Aus planes operating in G only will simply never install ADS-B out.)