In response to whether JC is either a "trendsetter" or a "follower", who knows, perhaps they are both... But what is a sure thing is that they, and many other religious institutions would do a lot better (spiritually, physically, etc.) if they were/attempted to be neither of the two. The best dancers are the ones who don't try, but truly attempt to feel, experience, and become one with the music - often mirrored by a soulful music within. When it comes to religious practice, I'm not a believer of trendsetting or following, I focus on what's inside and try to let it translate to the outside. Period. I think people forget that religious practice is largely 'ben adam l'makom' and not 'ben adam lechavero'. Sad.
The term 'Orthodox' has never referred to dramatic change, rather it has always alluded to a more traditional path, and been about maintaining a traditional level of religious practice.
The term 'Modern' on the other hand does and always has suggested an attempt to change things, sometimes (too) dramatically.
I question at times whether some aren't becoming more 'modern' than 'orthodox' - and being somewhat of a feminist religious Jewess (albeit still 'modern' enough that you might even be tempted to label me 'modern orthodox' - and how I loathe religious labels...), the concept of a female rabbinic position doesn't sit right with my more orthodox, traditional side..
'Just' my opinion, of course...