I certainly agree on the backpack. In future revisions I plan on making them a bit smaller and adding more details. We had some format issues that meant they didn't get the once over by Stefan before going to print. Sadly we didn't have time to resolve them so it'll have to wait until the next generation of them. With any luck that won't be too long though as the prints we ended up with aren't as crisp as I'd have liked.
More rivets on the armour? Good idea!
They're entirely modular so each component should eventually get an upgrade or alternative further down the line. There's going to be non boob plate armour too in the near future for folks who prefer that setup. I've got a set of jetpack legs on the go too.
As for bulkiness I think I can see where you're coming from, at least if you're thinking of GW's old models from the 1990s. I've not had a chance to take a proper look at the Svarog ones yet so I'm not sure how mine stack up with theirs.
A question for you - would you like to see more figure-hugging armour? I can have a go at that if it's something you'd like to see!