Why do you think Haggar needed a clone to spy on Voltron? What could she possibly do to a clone that she couldn't have done to the original? I suppose Ulaz could theoretically have disabled the webcam function when he uploaded coordinates to Shiro's arm, but I doubt anything of Haggar's would be that simple.
You know, that’s a very good question and I honestly don’t know that we’re going to get any answer at all for it. But -
if I was writing it, here’s how I’d tie up some of the loose ends of things.
Because honestly - not only 1. how did Haggar know that Shiro was going to become a paladin of Voltron (or does she just keep spare body parts of all her many many experiments lying around ‘just in case’?) to make a clone in the first place but 2. why did she make so darn many of him because even given the fact that some were ‘failures’ roughly eight hundred clones is a bit - excessive (and only viable as hidden spies just so often, certainly not eight hundred times)? So what the heck was going on with that?
I think Haggar getting a spy into the Voltron team via the clone was her being an opportunist. Which I love her for. But I don’t think it was her original plan at all - and very possibly not her end game either.
Haggar says he could have been their greatest weapon. She says this while calling him Champion. It indicates, to me at least, that his ‘ultimate weapon’ status was something she’d latched onto before he became the Black Paladin, back when he was still the Champion. She had plans for him then. He’s in possession of a very high tech Galra arm that can go up against ‘upgrades’ that came after it but even more his hand jacks him in to all kinds of Galra information and security systems. That’s - awfully weird to give a slave you’re not going to do anything else with.
Next point is that there’s no way Haggar could have known Shiro was going to find the Blue lion (or be on the team that did), rocket off to a castle that had been hidden for ten thousand years, wake up the only person in the universe that knew where the lions were, have just the right number of people with him for the team and then, to top it all off, become the Black Paladin himself and form Voltron. I don’t care how much you cover possibilities when you plan there is no sensible or believable way she could have planned for that. Even having the Red Lion in hand and suspecting where the Blue one was, still predicting Shiro’s roll in it all is - pretty wild at best and excessive at worst. I can’t imagine it would occur to her to try to put a slave, even an ultimate weapon, in the seat of one of the lions Zarkon was coveting to the point of insanity. That he did and it happened and he became the Black Paladin of a successful Voltron and took down a huge chunk of the Empire and her Emperor had to have been way out of left field.
Which leads us to point three. Because it was a good possibility she knew about Shiro’s condition but there’s no way she could have predicted how he would die. Yes, he did have a disease that was going to run a timer on him but there are a lot of things that could have happened to him and Team Voltron and him dying but the team surviving is plausible but pretty wiggly to try to predict, especially assuming that his team would be aware when he died if it happened. Because chances are nine out of ten getting killed while with your team is something someone would witness or you’d at least leave a body behind for. I’ve seen speculation that Shiro’s body was pulled loose and Haggar got it and all and while that’s interesting, it doesn’t look like canon went that way. So unless Haggar is going to predict incredibly well that he’s going to die when no one sees it and his body is going to poof so there’s no evidence - her coming up with a clone to replace him might make sense but she wouldn’t be betting on it. Dead people usually leave bodies behind. She might have kept a clone or two on hold ‘just in case’ but I can’t see Haggar putting all her eggs in that basket.
And lastly - she created an army of clones. You don’t send an army of clones to fill a single spot and you don’t let the rest of the clones wander around where they might give up the trick by being spotted. But she had close to eight hundred of those suckers on ice. (I keep saying eight hundred because there was a post drifting around that someone had counted them all and I’m just going to go with that number but even if it was only four hundred that’s still way too many clones for a one man job)
So we’ve got a role Haggar had planned for Shiro way back when he was a gladiator, that she created an entire army of clones of him for and chances are high the empty spot he left behind when he ‘died’ that she filled with a clone was just her being an opportunist.
Granted - it was an amazing opportunity and she’s far too smart not to take it. I am going to guess that she could do things with the clone - like take him over and see through his eyes and use him as a stand in for her with the White Lion - that she couldn’t do with the actual Shiro. Now the obvious answer for why she couldn’t do it with the actual Shiro is ‘because plot’ but if we’re going to fill in the writer’s blanks for them we can point out that taking over Shiro or at least spying with him in season one and two would have been the sensible thing for her to do and she never did. Haggar is, above all things, pretty darn sensible. So we’re going to have to assume that she simply couldn’t. Having access to a clone, grown from scratch and upgraded with a new arm that does more but looks the same, Haggar probably had more tinker time and a more specific purpose so the clone, and his arm, was probably outfitted as a unknowing spy from the start. You’ll remember that all those clones in the tubes had both arms and were based off Shiro’s younger form. One could speculate that she could have gone straight up ‘white tuft Shiro’ if simply replacing him had been her plan all along but she’s got younger version Shiro in there and obviously did ‘touch up’ (God, that’s horrible and its never even alluded to in canon) on the clone who eventually joined Team Voltron. She’d apparently been releasing clones singularly into the wild for some unknown time before then as well, so news of there only being four lions had obviously gotten around by then (remember Keith yelling it at the allies at dinner, so it wasn’t exactly a well guarded secret).
Anyway, indication is that the clone that joined the team was an opportunity and not one that Haggar had originally intended to use the clones for, just one she fixed up and put on the path when she saw the opening - and she tinkered with him to make him spy accessible for her purposes before she released him in ways she hadn’t with the original Shiro because her plans had been different when she’d been working on the original Shiro.
So - what was Haggar building an army of Shiros for (beyond fulfilling every fans’ dream)?
Let’s look at the way Shiro fights. He’s all over the place, isn’t he? He’ll use whatever weapon he has at hand. He’s incredibly graceful yet powerful and when he’s pissed he’s downright brutal. He tends to only have a passing acquaintance with gravity during fights and he’s incredibly adaptable and agile. He’s excellent at analyzing an opponents weak spots and he’s very skilled with Galra tech.
What else fights that way?
I give you the theory that, originally, Haggar was preparing to build an army of grasshopper robeasts and she was going to power them with Shiros. Things weren’t entirely in place. She was still working on getting the komar right and then she was going to have to figure out how to make it mobile and she was potentially still working out the schematics of making the robeast fluid enough but she had a lot of the pieces in place and Haggar plays for the long game. She figured out the komar and Lotor showed her how to create the kind of robeast/ship she needed. Losing her cloning facility with her pilots for the thing was probably a pretty hard hit - but, lucky lucky, opportunist that she is - she was given an entire Altean colony and plenty of time to exploit it.
Shiro could have been her greatest weapon. And if you think the Altean in the robeast ship was terrifying in a fight, I’d be even more so thinking of a several hundred Shiros in an army of those robeast-ships.
