The trade off to this is that the same section of my DPS is also mobile and seperate allowing me to supply healing/DPS in two places at once.You go way out on a limb here. The tradeoff is that they pour a significant amount of mana and time into destroying your minions which you can quickly replenish with next to no effort. If they attack your source of DPS they're not attacking you, that's the tradeoff.
No, that's a residual benefit of the main purpose - disconnected DPS - you can only attack one source at one time unless you use AoE attacks. It's in this residual benefit that most people believe there to be a problem. Assassins, like UB, can quite easily take down those minions however with Oak and Erebus, if they play intelligently, they'll try and move the fight amongst creeps - so that they're minions are being respawned as you're killing them. Oak has an even greater benefit of being able to place his little Wards down instead of it being tied to his direct position like Erebus. This isn't a problem with the minions, it's a problem with people fighting a General like they're an Assassin.
This is something I discovered after I fought one very clever TB as Erebus, who kept pulling me back away from the creeps and then AOEing down my minions. Before I realised his tactic, I was out of minions and had to run for the nearest creep wave, being AAed and eventually killed running. It's a matter of tactics per Demigod. Countering an Erebus who rushes your face with Minions and himself is a matter of disabling his minions - stunning if possible - or him, and then focusing on the opposite one. And of course it isn't easy to do, if it were minion builds would be pointless. As I stated in my original post, I do agree that the reward for fighting a General is currently disproportionate to the effort required, and offered a feasible solution.
I think they balanced minions to die frequently and be rapidly replaced (with the exception of yetis and shamblers, which only come four at a time and have more HP). To make them disposable but not completely useless against AoE characters they had to strike a balance on HP which resulted in them having more HP than most DGs can reasoanbly be expected to counter solo, which resulted in them being able to crush buildings and wander off independently.
I agree with your reasoning - however with a pure minion build, having minions that can be killed as easily as they've spawned would create a weak and utterly pointless build because one AoE attack away from a creep wave and you've just knocked out the primary source of DPS for your opposition - like what happened to me when I learnt this tactic. Having the ability to create strong Minions while having to sacrifice a General's solo ability allow for much greater flexibility. If Regulus can AA down towers without fear of damage, how is it unreasonable that a General can send his Minions in when the minions can be killed, and respawned, rather easily. If Rook can throw four towers on one lane, and then move other to another why is a General doing the same thing considering deal breaking?
I think their spawn mechanics clearly indicate their intended proximity to the general which summoned them.
I think both Oak's mechanic and the fact that they can
move disagrees whole heartedly.
You keep saying that if minions are by your side they'd might as well be removed completely or made invulnerable. I don't see the idea behind this. Minions are just another way to fight, no more or less interesting than the skills you replace with them if you choose to spec for it.
If minions were kept beside the General and unable to move away, you'd be fighting a singular source of DPS. The difference is that during the course of the battle, a General's DPS could be lessened compared to a Assassins. Open with an AoE attack on a General away from a creep wave and you've not only taken some of HP away, you've taken some of his DPS away as well. As it stands now, if I see an enemy about to AoE down my boys and I can't get them away in time, I'll move myself away and respawn them as best as I can before engaging the opposition. If the minions and I were unable to be seperated, I'd have to run away because no clever use of abilities is going to make up for a 20% health reduction and a 35% DPS reduction (random numbers pulled from thin air, take them with a grain of salt) before I've managed to land a blow.