Why the hell is Moore so hellbent on pitching the Moose to the police? It's a friggin' assault weapon platform, flight-capable to boot and clearly shown to have excellent offensive capabilities. Its defense leaves something to be desired, but it is a prototype; one assumes the final version would have better armor plating. Any military would fall all over itself to lay its hands on an armored fighting vehicle like that, and if Moore is so dumb he can't figure it out the CEO at least should be able to - especially since she makes it obvious that the company makes weapons and not robots "who can write a poem".
I would say that it is a matter of pride. He's old, dislikes AI and it seems like he's been part of big operations where big weapons played an important part, or, more sadly, he's a fanboy of those operations without ever having played a part in them. His operating the MOOSE shows him killing gangsters with joy, so he might like having control of situations, and the MOOSE pretty much screams power. It's not about creating an ideal product, it's more about showing that his way of doing thinks are better than Deon's.
How could a civilian site store a war machine loaded with not only cannons but heavy ordnance and prohibited cluster munitions ready to go? And even with the CEO being drunk enough to authorize it's deployment why was there no oversight at all?
So, after the end of the film, Chappie, Deon, and Yo-Landi are all in bodies where the batteries can be replaced, but are they going to have to steal a constant supply of batteries? Are they rechargeable or not?
The problem Chappie had with the Droid no.22 body was that the battery was not replaceable due to the damage the body had sustained from Hippo's bazooka blast. It's easy to assume that the droids batteries are rechargeable once pulled out - it would have been incredibly costly and impractical for Tetra Vaal if they weren't. And since Deon is the droids' creator, he may make some modifications in the future so that he, Chappie and Yolandi can recharge by just plugging to an energy source.
The batteries have to be charged somehow initially, so maybe they can recreate that. Or just keep making more batteries and recycling the old ones.
While Tetravaal does have rather lax security from the point of view of a audience use to big budget military bases, and objectively, there are some mitigating factors presented in universe for the Swiss-Cheese Security the largest one being that the most egregious lapses in security are during a massive and violent riot.
It's bad enough the lack of anyone checking the video cameras at Tetravaal, but they don't even have their own robots as security guards.
It's possible that they did. It's just that when the system was compromised, the Scouts that were charged with protecting the facility were taken completely offline to be repaired, and when Deon and Chappie looked for new bodies, these droids didn't show up as they were completely cut from the network by this point.
