RE: Backpack
I think it's an unfortunate result of making a toy emulate the Sunbow cartoon model with a Deluxe Class size/budget. As I said before, even some MPs end up with backpacks, like MP28 Hot Rod, MP Sunstreaker, MP44 Convoy etc. Now these toys are able to impressively compress their vehicle kibble, but again, they are larger and much dearer. Legacy Wildrider here must conform to the Deluxe Class size and budget, as well as stricter child safety laws (MPs are Ages 15+), plus it's basically a triple changer with the gestalt leg being the toy's tertiary mode. This toy is expected to achieve a lot with a limited size and budget allowance. Even MP Arcee still has a massive backpack despite being a big and expensive MP toy.
Looking at Wildrider's cartoon model, you can see that most of the vehicle parts pretty much vanish into thin air. The wheels are really the only part of the car that remains. Legacy Wildrider is trying to emulate this under the Deluxe restrictions, and it seems to do a fairly good job. The robot does look like the cartoon model, except with chunkier legs; because there would be even more kibble to contend with if the legs were made skinnier; plus budget wouldn't allow it. MPs can get away with this because they're super-expensive toys; well beyond the affordability of most children.
And as I said before, we do have choice. If you prefer your CHUG Wildrider to be less kibblerrific, then you have Combiner Wars Brake-Neck/Unite Warriors Wildrider. Plus, Brake-Neck has the bonus ability to be either an arm or leg, just like the G1 toy. But if you prefer a more G1 cartoon-like Wildrider, then that is what Legacy Wildrider is giving you. Yeah, the backpack is unfortunate - I'm not trying to say that it's great, but Legacy Wildrider is trying to give people something different, further spoiling collectors for choice. If you don't like this CHUG Wildrider, then just don't buy it and hang onto your CW Brake-Neck (which I think is still a really nice toy; Motormaster is the only CW Stunticon who lets the team down IMO).
That's freaking awesome! <3