What does it mean that the Believers Eastern Church (in Asia) is an "Ancient-Future Church"? Recently I was asked a question about the Believers Eastern Church and have been doing some research to find out what they believe. Here is part of what I discovered:

The founder and current Metropolitan Bishop of this group is K.P.Yohannan, who started a chapter of Gospel for Asia in Kerala, India, in 1981 and in 1983 established the Indian headquarters in Tiruvalla.  Since August 2018 K.P. Yohannan is known as Moran Mor Athanasius Yohan Metropolitan in relation to church duties. Believers Eastern Church (previously Believers Church) is self-described as "evangelical in nature and outlook, oriental in worship, democratic in function and Protestant (Episcopal) in governance and character". The Believers Eastern Church is an "Ancient-Future Church" and as such, is considered by some to be heretical.  Source: https://www.wikiwand.com/en/K._P._Yohannan

The Nicene Creed is the official statement of faith for the Believers Eastern Church.  The Church is Trinitarian and accepts and confesses the historic Creed of Nicaea, Constantinople and Ephesus.  Source: https://www.bec.org/faith-and-beliefs/

I noted that although this church is "Protestant in governance and character" that does not mean to say it is Protestant in belief.  It also says it is "oriental in worship".

My main concern is with the claim (by some) that because it is an "Ancient-Future Church" it is heretical.  

What does it mean to be an "Ancient-Future Church"? 

Edit: I suspect there are several churches claiming to be "Ancient-Future" and insights into what "Ancient-Future" means is helpful.  However, my main question is about the Believers Eastern Church and because it is an "Ancient-Future Church" some people brand it as heretical. Theologicaly speaking, what would make an "Ancient-Future Church" heretical?
On the surface, ancient-future churches claim to speak across generations and draw equally upon ancient (hymns, chant, candles, communion) and techno-modern (alt. rock, art, ambient, projection, video) sources. An American example of this would be the hi-tech megachurches that host anything from rock concerts to communions.

Underneath that modern, millenial-attracting exterior lies a method developed re-design &amp; re-purpose churches, emphasizing proselytization &amp; assimilation:

 

(from Ancient-Future Evangelism: Making Your Church a Faith-Forming Community)

It endeavours to reach its goal by introducing "levels", akin to New-Age religions such as Scientology.



In sociology, this concept is called gamification and is widespread in social networks and mobile apps. Gamification is hugely popular amongst millenials and Generation Z.

Ancient-Future is a reaction to attempt countering the decline in worldwide religiosity, which is especially hurting first-world Christianity. According to the latest Pew studies on the matter, the regional percentage of the population identifying as Christian will decline significantly in Western regions by 2050:



The situation for Asia is a stagnant, but this is largely due to Christianity being concentrated in just a few Asian countries with a higher birth rate than the West.



The motivations for this modernized recruitment approach are twofold: 


many millenials grow up much less influenced and knowledgeable of doctrine as the previous generations. They also grew up and are accustomed to virtually immediate access to scientific facts and are as a result, better versed in critical thinking
the most loyal age group in first-world churches will be largely deceased by 2050