I've been a staunch supporter from the start.
There were two main reasons why something had to be done to address the downward trend in overtaking. First is the oft-debated dependency on Aero-Grip that was inevitably disrupted when coming in close proximity to another vehicle. Second was the disturbing pattern in which drivers were defending their positions. When the prevailing consensus was that overtaking was "nigh on impossible", the leading driver was emboldened and felt entitled to defend in a manner that was inconsistent with driver etiquette from years gone by. Add in the amazing advancements in Safety and what you had was a disproportionate advantage being held by the driver in front, on the track and mentally inside the helmet. Generations of drivers were coming up in an environment where fair-play took a back seat, they were hell bent on retaining positions because they knew the difficulties that would follow when they entered the turbulence behind.
As for the "unlimited use" debate. It was definitely the drivers that pushed for the end of its unabated use in practice and qualifying. And I'm glad they did. Unlimited use only goes to serve the best cars. There's no doubt that this has aided Vettel/RBR over the past few seasons in qualifying. It just stands to reason that a car that is glued to the road will reap substantially better benefits in such a scenario.
The notion that DRS was simply catering to casual fans doesn't stand up. The OWG (Overtaking Working Group) had been studying the issues surrounding overtaking for years, conducting numerous surveys across global platforms in order to better understand what motorsport fans of all stripes were looking for in Formula One. Time and again fans from every walk of life cried for more passing.
Having watched many, many races (from the late 70's through today) in a condensed time span like I have, has given me quite a perspective of what Formula One racing has looked like over the years. The one thing that sticks out as the most frustrating thing to watch is a car that is visibly faster being held up by a car that is significantly slower. Sure, you would see this occasionally in the 80's, and then increasingly more often in the 90's, but by the 2000's this was a race by race occurrence for somebody, and while the racing was technologically exquisite, the entertainment value left something to be desired.
It's clear by now that most naysayers will never be swayed on this issue, and in fact become more entrenched every year. But I'm quite sure that the DRS isn't going anywhere. More and more junior formulae will be introducing the concept, ushering in an era of drivers that will have better respect for each other when battling for position knowing that they'll have a fair shake to get back at them sooner or later.