Are you sure that ad blockers are the only variable in play here?
"(October 2014) we had nearly 4.5 million hits (read) on our articles. This year (October 2015) we are at 4.4 million hits...
Where a year ago we served 375~400K pageviews per day, we now register just over 200K pageviews a day."
Is pageviews the actual metric, or is ads served the metric? Given the recent discoveries in how many "ad views" were actually never presented to the reader and were just phony revenue ticks, could it not be that you are also "suffering" from an ongoing reduction in phony ad presentations as the trickery is discovered and addressed?
I block ads primarily to limit tracking and bogus traffic, not to dodge advertising per se. I heartily endorse jfoutz's suggestions here. If you continue to serve quality content, it's the more sustainable business model long-term anyway.
Years before the modern ad-network paradigm, many media sites were subscription from the outset (e.g. WSJ, mercurynews). Some later went free, using ad networks to pay the way. Now, the trend is moving back to a subscription model. Those sites that do the punitive block-ads-and-we-block-you (e.g. washingtonpost) will find that people just go elsewhere for those stories.