You've posted this before and it is seriously the most laughable thing I have ever read as a want or need for a pocketable device. The day I have to do PS or AC work on a four inch screen is the day I point a shotgun at my nads and pull the trigger, as that would be more fun.
No I wouldn't want to do PS or AutoCAD on a 4 inch phone either. But, a 5 inch phone with high resolution makes it possible. I can not imagine trying to create any significant AutoCAD drawing on a phone of any size but being able to view drawings and pull dimensions IS something I'd like to do.
Now PS is more doable on a phone so long as the screen is large enough and of high resolution. The problem with PS is that it is VERY much a memory hog and it will be a couple more generations before 2GB is a common option.
The biggest issue with either a phone or a tablet is the lack of a true mouse. Doing any major work with AutoCAD is going to really demand a better input device than a touch screen interface.
But, getting back to the original reason I posted, the fact is the industry is moving to larger phones and the customers are buying them. Apple will likely upgrade to a larger display and is capable of going to 4 inch or larger without increasing the package size. There is just some things that are better on a larger display and as more people do more of there internet and PC activities on a phone that will continue to push towards larger phones.
But, once again, you can continue to use a smaller phone -- who am I to tell you what sized phone you should use. Just know that the higher functionality will be limited to the larger high resolution phones. One thing that will offset this is a phones hotspot feature which can permit even a small phone to do much more if you use it to drive a laptop or tablet. But, if a large phone is an inconvenience then lugging a laptop or tablet isn't going to be any easier...
Brian