I think the direction they were going was that the crazed robots from the first film (Dispensor, Xbot, Phone Guy) had no "souls" because they were simply regular objects infused with a great amount of Energon. The "Allspark shard"/Energon Cube shard simply has enough Energon-dispensing powers left in it to revive Megatron and Jetfire, who--since they were actually built and designed as TFs--simply get revived rather than anything else. Kind of like how your car will sit dormant forever if it doesn't have any gas, but as soon as you throw some in it'll start right up. (Assuming the battery hasn't gone dead or anything else.) This is the same reason why it's stated in ROTF that the hatchlings will die without any Energon.
Have we ever actually had a character officially commit suicide before? We've had characters sacrifice themselves for others in the face of certain death or refuse healing to save others (Dinobot, Sunstreaker in AHM, Optimus Prime numerous times) or ignore certain deathly qualities (Ironfist in Last Stand of the Wreckers) but have we ever had a character actually pull the trigger, per se?
I have actually said in the past that, by watching the shows themselves, it becomes blatantly obvious that the TFs are advanced enough that they don't need to abide by our understanding of the laws of physics. (In other words, it is entirely possible they have technology that can literally destroy energy.)Hey, all this talk just gave me a thought: energy can't be destroyed, only transmuted, so if the Transformers have been fighting a war for millions of years run on Energon, which they consume both to keep their bodies fueled AND to power their weapons... where the hell has all that energy gone? Is it super hot on Cybertron, it's just radiating waste-heat from every bot's action? Or are they farting it out a la ROTF Jetfire and it's being contained in a gas atmosphere around the planet? Or are all those lasers just getting blasted into space after they hit their target and glance off?
Unicron never actually absorbs the sparks of any Transformers, does he? I mean, the concept wasn't really around in TFTM, but if Unicron was eating and digesting various TFs he ate from the moons (A guy who looks like Beachcomber is dropped into the vat) it's possible that their sparks still returned to Primus after being extinguished.Would that not mean that a majority of TFs would have to die for Primus to return to "life"? Would that mean Unicron killing all the bots is actually fueling his enemy, or is Unicron HOARDING all those Sparks so Primus cannot awaken? I love the philosophy-chain that has arisen in this thread!
Also, the whole point between the difference of Unicron and Primus is that Primus doesn't need to be "alive" again. His essence lives on in every Transformer, whose explicit purpose is "be around to stop Unicron, because eventually he's going to come after us." As a being of Generic Good, Primus can create life, and as a being of Generic Bad, Unicron can only corrupt it. (Much like God can create life and Satan can only corrupt.) Primus created life with the rock ball he was in; Unicron corrupted the ball until it could transform into his robot mode.