There have been many very good points raised in this thread. As a relatively new member it's hard for me to judge whether the forum really has changed or whether it's just my perceptions of this hobby. I guess it's different for everyone but for me it's probably a combination of many of the points listed.
Acceptable quality high-output flashlights are now mainstream and affordable and LED flashlights is no longer a new and boutique field of endeavour. This is bound to skew the demographic of CPF membership as the NEED to mod or build your own has been reduced (though it's still an interesting hobby).
Creating something like a build thread can be intimidating. I have tinkered with a few little projects at home but I often assume that they may not be of interest to anyone but myself. Also, it certainly is a lot of work to document and compose a decent build thread. Having spent many years designing training materials professionally I have realised that content creation is not a task that everyone can do well. Having said that I certainly still enjoy reading the threads created by others and have learned a lot from them.
Tablets and other mobile devices certainly do make posting content to the forum more difficult than on a regular PC. At least, I still find it that way. Whilst I find Safari on the iPad to be relatively usable I have had a lot of minor UI frustrations with the browsers on my android tablet and phone. Additionally the take-up and popularity of portable devices means that we can login for a spare five minutes simply to read in situations where we wouldn't necessarily have time to fire up a PC and post in-depth stuff.
I thought it was just my own perception after a couple of years of membership but it's interesting that some of you have commented that many people tend to simply ask questions rather than research the forum. It certainly seems to me that the same old questions keep popping up time after time in new threads which gets a bit stale.
I believe there is a valid perception that CPF content is skewed towards the more expensive sections of the market. Whilst I have found most people here to be extremely helpful, I know for fact that some members have moved on because they felt this forum was becoming a bit too elitist. Some of those members now frequent other forums where a lot of interesting modding and build threads can be found. What I do not find so attractive is the hostility that some members here and elsewhere display towards the perceived "competition".
Lastly, whilst I understand that the first rule of CPF is that we don't question the rules of CPF, I personally find that some of the restrictions no matter how well-intentioned end up making information more difficult to find than it needs to be. Even with the best of intentions I have had a few posts modified or deleted for reasons that still aren't entirely clear. This is simply a personal observation on my part and I know not everyone sees it this way.
I still have an active interest in things like alternative energy (and even flashlights
) and I hope to keep finding useful information for many years to come. But it seems that currently we may have to search through a lot of mundane threads to find the gems. And this will be no different anywhere else.
Sounds like my boss
Too often I read posts from people who feel a need to make snide comments rather than just "turn" the page. 
