So really this arguement holds no value but to enterain each of us becuase we can't say really anything is bigger or smaller. I have enjoyed the convo ty. I think we have taken this a little of topic for two long what do you say?
I think there's a possibility you might be forgetting that the FX department utilized a different camera POV for their renders of Destiny.
This in turn makes numerous things out of whack size-wise.
I will say this for Destiny... it's relatively large... with most of it's size going in length.
The ship is the widest/thickest at the crescent moon shaped section where the engines are located.
The Stargate Wiki for example places the following sizes for the ship:
Length: Roughly 2,450 feet
Width: Roughly 1,700 feet (at wingtips)
And let's not forget that 'wiki' of any kind is highly subjective and open to personal interpretation.
I would however agree more or less with the sizes as presented above because they do 'appear' more or less consistent with what we saw on-screen.
As for why it took a whole generation to build the ship:
Several explanations present themselves, one of which would be that the Ancients were nowhere near the level of technology as when they created Atlantis for example.
Much more primitive, space-faring yes and more advanced than us, but I would suspect they spent a whole generation to make the thing because of the nature of it's mission.
They had to work out various long-term equations so the ship would be able to go on... especially for millions of years.
Contemporary Humans on the other hand had help from the Asgard for example who were close to the level of technology of the Ancients, hence constructing hyperspace ships such as Deadelus was not difficult (and besides, that ship was never meant to be sent on a mission to unravel what makes the universe tick).
In any event, I veered off topic.
In terms of what I would like to get on-board Destiny if SG Command was able to provide support:
Raw materials that can be used to repair the ship's hull and damaged systems.
Everything necessary to bring the ship back up to it's full operational peak (though some flaws are bound to remain due to the age of the ship).
Maybe it would be possible to incorporate more powerful shields and better weapons into existing systems, or ways to simply enhance what they currently have.
Even if the Destiny was not built with the same tech level as Atlantis did (obviously the ship is much older in tech development), it would still be much more advanced than anything on Earth (sans Atlantis itself), and likely has some kind of a recycling capability that would allow for conversion of raw material into something usable.
Earth could have also sent more personnel who would be willing to work under the current crew, bring in more specialized individuals to help with the ship, disassemble and reassemble several fighters that could be used if possible.
Some entertainment for the crew, and that's about it.