Ha, I swear I wasn't stalking this thread, I just happened to check it now.
Ok, I see what you mean. Yes, a com and 3 solars have more combined hitpoints than just a commander, so I suppose you could say it will 'take more to kill them", and so forth, and I guess that is your reasoning.
But you have to be careful not to get lost in pure numbers. It is good to use numbers as a check, but they need to
mean something in realistic ingame scenarios. Realistically, you aren't going to lose your commander at the game start (barring some cheese/all-in you don't scout, but then you rather deserve it). While solars on the other hand tend to be very vulnerable to things like napalm bombers, or even just scouts that poke them closed a bit. So while com+solars has larger numbers in hp, a com with energy production is actually
safer. It seems counter-intuitive, but I am quite serious. Some of my early game is just about trying to energy stall the opponent a bit. And
this is harder to do to the energy module. Because its not about picking off one, or nudging a few closed a bit. It's all or nothing trying to kill the commander.
Now it's not like the difference between +6 and +8 is game breaking. But you have to remember when it comes to unlocks, everything is supposed to be balanced slightly underpowered when it doubt, for reasons I already described.
I think the main problem is, it is useless at higher morph levels because of the inherent morph bonuses, which all tend toward better combat abilities, even for eco com. So you only want to morph your com to use it offensively, otherwise those offensive abilities go to waste. So you would never equip modules for higher morphs that would leave your com better off sitting in your base.