I have the following idea and would like to see it implemented. Development time cannot be much really and I believe it would be a lot of fun and also very powerful game feedback and tactics can be attained by their use.
Here goes:
Creation of basically a Holo-Deck -a la PvP- where you can select from a list:
a) The Opponent you wish to battle. (any from current list from Kobolds to Living Spells & Orthon´s +)
b) The Difficulty Setting (N / H / E)
c) The Quantity.
d) The Environment. (Could be any existing quest environment or say 3-5 to choose from like Arenas)
Once you zone in you have 1 minute to buff and go at it.
I personally would enjoy this feature as something I would use to measure the effectiveness of different AC/DPS ratios, as well as Spells, Saves, Tactics, etc...
What do you think?