While he was seen as pro, that doesn't mean his opponents could not use his words against him. Pragmatically, his reasoning is the core of the state restrictions being declared constitutional by the default of SCOTUS dealing with the state restriction cases.
So is Heller a net win - theoretically yes, practically - the jury is out on whether it advanced gun rights in many locales. Is DC practically better on gun ownership - I'm not tuned in the population there to know. Maybe someone does.
Gun rights are a tricky thing. A small but similar case is that of OC in TX. It passed after an acrimonious debate in the gun world as it might have negative practical consequences. I saw someone on another forum all excited recently about how it has been a success! WOW!
Practically, it is very, very rare. So it's utility is not being seen in the gun carrying behavior of the vast majority of Texas LTC holders.
What is has done is knock a big hole in the no-carry signs. Originally, TX businesses could ban carry with trivial signs like a Ghostbusters sign. Then clever gun folks got the legislature to modify the sign requirements for the 30.06 sign which was truly large and obnoxious. It had to be exact to be enforceable. Many businesses chose not to post them as they were obnoxious.
Then came OC and the shenanigans of some of the OC folks marching around with ARs or AKs and the infamous Chipolte twins - less than attractive icons for the gun world. The idea of exposed carry guns was such that many businesses including major stores, buildings and restaurants started to post 30.07 signs that banned open carry. So it made practical OC quite a diminished utility. I can't (even if I wanted to OC in the biggest supermarket chain and many other places I frequent). Thus, I would have leave the gun in the car and prance around with an idiotic empty holster?
But even worse, as stores started to post the 30.07 signs quite a few added the 30.06 sign. If you have one antigun sign - might go for the whole nine yards.
Thus, the so-called expansion of a right hardly used caused a major loss of carry locales and the PR negative of kids and folks seeing signs saying gun carry is bad.
Now someone will post - Well, I don't go to businesses that ban, blah, blah. Good for you - it is not practical if you leave a normal life and are not bloviating. We lost practically but won theoretically.
There have been no effective boycotts or businesses folding over the issue. A long restaurant - only with a 30.07 - told me that they had two old coots having a hissy but that was it. Most folks were happy not to see the average OC type at dinner. The restaurant had no problem with concealment.
So to end this line of thought - was Heller a theoretic win but lead to practical and negative unintended consequences.
Perhaps, Trump could get enough Justices to take a case that would negative the state restrictions and overturn them. They might weaken Scalia's meanderings (supposedly well researched but not in the true theoretic mode of what I think the RKBA meant). But I don't trust even conservative justices. Plenty of conservatives go down the Zumbo, Metcalf road. I suspect the conservative moneyed classes might be skeptical of the lower classes with military style arms.
It might lead to the guillotine for CEOs who make $300,000,000 by raising the price of needed medicines to outrageous levels from previous reasonable prices.
We will see if Trump is true to his RKBA promises. Heller's meanderings might be undone with legislation. As civil rights legislation got rid of noxious state discriminatory laws, perhaps a similar approach to gun rights would lead to Gov. Brown and Gov. Cuomo standing in the doors of the gun shop and being removed by Federal Forces after they tried to get the state militias to forbid the free exercise of the RKBA. Wouldn't that make a great picture?