The fact that DLR is in the middle of a large city means it has more restrictions than a place like WDW regarding fireworks. Aside from the expense issue of fireworks, it is my understanding that DLR's city location is one of the reasons they only show fireworks during peak times and on weekends (to reduce the annoyance on local residents). It is also one of the differences of which WDW vets should be firmly aware - entertainment offerings at DLR are not as regular year round as they are at WDW. Visiting off-season at DLR has more downsides than at WDW because of reduced opportunities to see the excellent shows at DLR.
In any case, the OP is correct and everyone should understand this. I summarized this in my thread "HydroGuy's Fireworks Rule"
www.disboards.com/showthread.php?t=1199851
If you want to see the fireworks at DL, do not save fireworks for the last night of your trip. Plan to see them as early in the trip as possible.
Further, I do not think summer months are "safe" months for fireworks. Last summer the fireworks were cancelled one week five times. Yes, I typed that right. Five times! This is not typical, but it is possible. Cancellations are fairly regular during the summer (at least once a week).
As mentioned, if you are visiting DLR in off-season, your opportunuties to see the fireworks (and several other shows for that matter) will be restricted to weekends. So if you want to see the entertainment, you will need to overlap your trip with a weekend night (Fri/Sat/Sun). But if you only have one weekend night you will risk missing the fireworks if they get cancelled. And by visiting over a weekend you will likely see crowds on weekends year round that look like peak season crowds because DLR has so many local AP holders.
If you visit during a busier time of year, the fireworks and other entertainment will be performed every night. When this happens, there is no advantage and significant disadvantages to visiting over a weekend. So stick with weekdays if possible. And see the fireworks early in your trip.
Finally, for those who have not seen Remember Dreams Come True, it is hard to describe how awesome this show is. It more than fireworks, with lasers and special effects that will know your socks off. IMO it is better than any of the shows at WDW including Illuminations.