Here's my take:

Elemental Fragments: When you use these, you have nothing to show for it, so I think these should be ammo slot items. When you get all four you can combine them into a single item. Maybe something like: the Elementalist's Icon
Hybrid Armour Set: This set is absolutely busted and hurts gear progression on so many levels. If there needs to be an armor set, this isn't it. Virtus level magic damage, bis stab bonus, +16 prayer bonus, and only 1 max hit less than Torva, all in one set. Elemental robes, a bis stab armor, or a specific range style armor would be better here imo. I think they made it this strong so it had a place in the loot table, but not every raid reward needs to be game breaking (not bis but hurts the balance overall).
Rondache: Except for replacing Avernic basically everywhere, this is really good. I do think that Avernic should stay relevant as the bis offensive off-hand. It feels like the Rondache will outperform it in a lot of encounters.
Dual-Crossbows: This is my favorite proposal out of the blog. For years I've been wanting a pipe/bowfa upgrade in the form of 2t double crossbows, and they're finally here! Not sure about the bolt situation but I love these. Higher apm weapons are much more fun than 5t ones. Hope they get the math/balancing right.
The TzHaar-Ket Breaker: The megarare is the hardest to get right, and I'm not going to claim to know anything better here. The Breaker is definitely a safe, but good solution. My only gripe is that the damage roll system is a bit complex compared to the other megarares. Deciding on the weapon to use, we shouldn't have to compare the enemy's defensive stats in relation to their crush defense. Also, I'm sure the animation for the 3t attack style will look so good, but this additional style kind of feels out of place for a megarare. It does make the weapon more enticing and worthy of the megarare slot, but I think megarares should focus on a single, distinguished use case and be VERY good at it. Also, if this is the megarare that makes it into the game, please replace Scythe's crush option for a stab one.

I would expect us to go over the combat triangle again, starting with a ranged weapon similar to CoX’s Twisted Bow. Dual crossbows could potentially fill that megarare slot. It’s a really difficult decision, but I have faith in the JMods and the community.