Michael, why would people edit raw files on and uncalibrated screen and how many raw files can be put on an iPad or iPhone???
I guess it might be a feature down the line but at this time there are a lot more important things to get working first, I would say keywording for one...
The likely real reason why Adobe doesn't do this yet even though many people have requested it is that it would cost them dearly in bandwidth and storage capacities. Right now only smallish lossy compressed, downscaled dngs or simple jpegs travel to and from Adobe's servers which is tenable. Sending full raw files from 24+ MP cameras is probably not something they can realistically do yet. Having the iPad try to generate the lossy dng will likely show how very low powered they are in comparison to a simple laptop and is likely not yet a realistic solution so you'd still have to send the file online and have the dng generated by a server.
I use the mobile thing for simple iPad slideshows and simple portfolios. The color is really good as the current generation of iPad screens is very well done with close to sRGB gamut. I'll sometimes do some simple edits but it is really not very useful for that yet. It shows promise but is not useful as a laptop replacement yet on trips. You're better off getting a lightweight laptop (many cheapo ultralight windows ones out there nowadays and the MacBook Airs are great for this) and running the full Lightroom on that if you are traveling.
See The Field Triage Opportunity for Lr Mobile for Adobe's thinking on the topic. It'll come one day, but other workflows are coming first.
It's best not to think of LrMobile on the iPad as a laptop substitute - even if I upgraded my perfectly good iPad 32Gb, it wouldn't get me far with the two 32Gb in my Nikon D800. Instead it's more of a loop away from the desktop. Lightroom for the pub? So I use it for portfolios, casually reviewing shoots and making ball park adjustments, in that order, and the tightly-related Lightroom Web is the easiest way to set up a simple method for people to select images they want via their browsers.