Coding it is not a problem anymore, its the time and technology.
DN had the throne for a while. Everyone was saying YGOPro is not as good etc. Now, we got this situation: YGOPro is being more frequently updated with automatic stuff than DN for manual. I mean just compare what it takes to code pendulum system in automatic system so that all cards behave accordingly as well and on the other side just add few functions so you can place cards manually onto new two fields in DN and still, in YGOPro its been added for a while now, where DN is still struggling with the update.
All this means a lot, especially when Pro has more modes, more things to do even automatically, like different formats, altering rules, tag duels etc, AI script which is remarkable now and on can test pretty good on it, it begins to ruin the glorious DN. Just look at the downloads and reviews on Android app for Pro.... 100,000+ downloads and 17k+ ppl rated the product as great, and its still in the beginning phase to adapt it to android. I've been playing it, its so good lol. I can duel AI, if its easy I just use Cheating AI script to test my decks, I can play it anytime anywhere, it does not consume that much battery as some high games out there so yeah, and I don't have to worry about thousands of effects cuz all is done by system automatically :D
This is the power of open source.
So, BLS can code it no problem, but he knows and we know its already too late for that.