The iPad/Tablet product is always going to have limitations for this kind of stuff based on the core audio design...I have a few DAW proggys I can run on the ipad but they are really toys compared to a real DAW.
As far as running Sonar (or any other real daw platform) why would you want ti excpet to snatch some audio in a live remote situation and in that case your limitation is going to be gear...(mics/pre's/etc)
The one place I have found the ipad to shine in is in being a control surface and also keeping track of trax and songlist...
AC7 Core is a great program and only a little cludgey to get going...
I have also found a good metric on the tablets for software cost, some of the engineering programs are way above the price-per-point I paid for them...