For many reasons, this is a great ship. It is a very customized feeling cruiser, in that it has a wider range of abilities compared to the standard tank (e.g. cloak, cannons, lance).
I am glad to see it being promoted once again, as it seemed to be forgotten somewhat after the odyssey came out.
Granted, the lance could use some more power, and the engine power/turn rate might be better if increased (consider the 3rd nacelle), I still find this ship very sturdy and versatile.
Of all my concerns of this ship, I would love to see a Fleet version available. An elite version of the Galaxy Dreadnought only purchaseable by say, Tier 5 fleet starbase members. I would suggest improving the lance significantly on this version, and improve the cloak to a battle-cloak [yes, it would be nice to cloak whenever, not wait till the red alert stands down...] Additionally, adding a saucer separation would be neat, as its predecessor (the 1st Enterprise D) had it built in standard. Finally, Increase the crew overall. It is a big ship with near the HP of the Odyssey. There is little reason for it to have a mere 1k crew when it could get away with maybe 1,500 or even 1,750. This would allow for faster repair rate and overall (slightly) better performance.