My, my, that was uncalled for. It's alright though. 
Let's squash the beef.
I was too lazy to go into the depth at the time but to sastify your curiosity; I'll justify my earlier statement now:
Overview: Obtaining required dups will be too easy and said weapons will be gained very quickly
With the current system (i.e battle coins)
Adding (as the rewards were in the first event) 5 guaranteed rare pieces to the rare perk box, an entire rare weapon to the epic crate and a full epic weapon to the legendary perk box will destroy the game's current balance.
How?
Players will be spamming event battles, grinding battle coins and in a matter of three days everyone will have the epic and rare duplicates they so desire. Which isn't healthy for the game's economy.
- It'll be much like the guild exploit we had a few months back but far worse
For the average grinder, yes it's like being served fruit on a platter of beaten gold but for Rovio; it's not the most ideal situation by far.
- Do events need better rewards than just legendary perks: Yes
- Should weapons be iterated into the rewards: With the current system, No
That's how I see it, perhaps there's more to it, maybe I'm wrong (if so, im always up for a good debate ) however that's all my input to the topic.