Yeah, writers make mistakes and rectify them in future series. That's been a trend that's been ongoing from series to series (I'd argue that Johto brought about more mistakes than improvements, but...). But... for whatever reason, BW has gone against this trend and very few things have improved from DP. It's been over a year now, so I think it's a fair assessment to make that BW thus far is a huge step backwards from DP, which obliterates the order this entire show had established. Could they rectify their mistakes? Maybe, but I certainly don't believe BW's going to suddenly get awesome in the middle of its tenure and start improving on everything again. For all the opportunities they've passed up, I think BW's going to stay the course and there's no telling if the Gen VI series will improve on that or not. Even if it does improve, it's got a lot of a mess to fix, so it'd be a stretch to say it's a logical progression.Its never too late to fix things.Writers tend to screw things up many times in past,but they always managed to prove how they have knowledge and skill to get characters and story back on right track fixing their misplays.
Of course, for BW the writers have written themselves in a hole because they just had to go and outright state Ash's age at the very beginning. So if the next series does try to rectify this issue by making him older (assuming they still keep him on), it's still not going to fix the mess of the past 700+ episodes happening in the span of a year which means things still won't make any fucking sense.
Seriously, I view the Pokemon League as the Pokemon world's equivalent of our Superbowl. These things happen annually in my mind. The idea of all these mega-important Leagues and all the shit in between happening in the span of a year is just... no. Can't accept that as the truth. These writers can fuck off.
Really, they had the perfect thing by not outright mentioning Ash's age at all. Sure, there were debates, but everything in the anime is debated about at some point. And the ambiguity let us all believe what we wanted to believe. BW's robbed us of this, so unless the writers outright state next series "Yeeeeah, we realize how improbable and stupid it is that our entire series based on an ongoing journey that's spanned across over a decade in real time has all happened in the span of a year in the show's canon time. Sorry about that. We'll make Ash a more reasonable age next series and retcon what we said in the beginning of BW so everything makes sense again!"...
... As much as I would love for the writers to outright admit their fuck-up, I do not think they're going to do that. They dug their hole, and any attempt other than what I mentioned won't help matters.
Unless we just assume Ash died way back in Kanto, Pikachu keeps his bodily functions active by zapping him frequently, and he drains the youthful energy of every girl he travels with to maintain a constant state of age 10 without his body decomposing (i.e. Ash is a zombie).
Either way, it's full of shit. They should've kept this under wraps; there was no reason whatsoever to state Ash's age at BW's beginning as it is.