I agree with EVERYTHING you said. If subs, amps, or batteries have close enough specs, then they should be kept open. If one product is obviously better than the other (Kicker CVR vs AA Havoc), it should be locked.
Recently in subwoofer comparison threads, people have been naming power (amps), enclosure size, tuning, and goal. Imo, if threads contain that and if subs are similar, they shouldn't be locked