Hmm, for the benefit of the fans, I'd agree that taking away diversity in machines is taking away a large element of competition. I'm of the opinion that motorsport is very much a teamsport, not at all about individuals. Taking away the freedom to use a different car, different engines, etc, is taking away some of the interest in the battles and also I would contest that it hampers the on track-battles.
If everyone has the same car and everyone is of similar skill, then its going to take that bit more to create overtaking battles. The classic battles of the past have been between different chassis, drivetrains, engines, tyres..never usually the same.
On the other hand, from a drivers point of view, the more options in motorsport, the better. Also making it cheaper with spec chassis is entirely necessary at the moment. The sport overall (not just ALMS) is badly structured compared to other sports as it relies a lot on competitors bringing the cash.
Personally, I'd hate to see non-spec racing disappear and I only view spec racing as a temporary stop-gap till someone works out a better solution for making motor racing more economically sensible and still competitive with a focus remaining on teamwork.
(this is not to say spec series don't feature team work, I just feel taking away one of the team work variables doesn't help racing.)