You're still limited in size of the image file. Larger files are harder for most filesystems to handle appropriately, makes little-to-no use of the benefits of a journaled (IIRC) filesystem.. and is more easily corruptible.

Again.. I think the image way is great if you have a specific set of small software you want from debian.. and that's it.

If you plan to install various different cool software you find in the repo's just to try it out.. and experiment on the debian side ... I would recommend using a full partition.

Speed never really had any determination into why I always recommended partitions... although it's great you were able to speed up the image .. for anything beyond using debian as a host for a couple apps I think you'd be better off with a ext3 part on your SD card... and swap.

The OP is describing loading a Web Server, a Mysql Server, essentially turning this tablet into a LAMP server.. now I doubt he/she will be doing any benchtesting or massive web-serving from a tablet.. but that's still a bit beyond what is meant for an image file IMHO.

Of course.. everyone is entitled to a different approach .