Actually, I think DDing into the enemies' back rank is great tactics: your caster (arguably your most versatile party resource) sacrifices his turn to bring two or three beatsticks right where they need to be to lay the smack down NOW. Why shouldn't that be the spell's intention?
The spell description contains nothing about your allies' initiative, their losing an action, or whatever. They only have to be "in contact with each other", which is easily satisfied by grabbing your neighbours' sleeves - a free action in my book. The designers could easily have extended the "turn ends" mechanic to all transported creatures, but they didn't do so. This means you can - and should - use DD to instigate several well timed full attacks on the BBEG ad once.
Dimension Door is, regardless of the "long" range entry, essentially short range teleportation (a few hundred meters on the outside). It is intended at least as much for tactical usage as for general-purpose transportation, and IMO, it is much, much more a tactical than a utility spell.